Heterogeneity of keratin intermediate filaments expression in human glioma cell lines.

Keratin intermediate filaments (Ifs) are specific for epithelial cell differentiation. This study demonstrates the presence of keratin in two recently established human glioblastoma cell lines 8-MG-BA and 42-MG-BA. Immunofluorescence staining was performed on cells within passage 230 to 235 using monoclonal pan-cytokeratin antibodies. The cells were analyzed during several DIV at different cell density. Keratin-positive stained cells reached 5 to 7% in 8-MG-BA and less than 0.1% in 42-MG-BA cell line. The presence of keratin-positive cells was independent on cell density and days in vitro. Keratin-positive cells appeared unevenly distributed in both cell lines. They were observed as single or areas of keratin-positive cells. The morphological features of keratin-positive and keratin-negative cells were similar. The results are discussed with respect to previous studies on glial fibrillary acidic protein (GFAP) and vimentin to show the heterogeneity of IFs expression in glioma cell lines.

Comparison of two non-anthracycline-containing regimens for elderly patients with diffuse large-cell non Hodgkin's lymphoma--possible pitfalls in results reporting and interpretation.

Age over 65 years is a risk factor per se for doxorubicin administration, and coexisting diseases pose additional problems. There is still controversy whether chemotherapy regimens for elderly patients with aggressive NHL should be full-dose doxorubicin containing or whether development of non-anthracycline containing regimens is warranted. In this prospective study, 47 patients aged over 65 years with diffuse large cell NHL clinical Stage I/IE bulky-IV and no other initial exclusion criteria were randomized to receive either BCNU 120 mg/m2 d. l, VP 16 60 mg/in2 d.2-4, procarbazine 85 mg/m2 d. 2-8 (arm A, 27 patients) or mitoxantrone 6 mg/m2 d. l. with VP16 and procarbazine in the same dosage and schedule (Arm B, 20 patients). Partial responders received additional irradiation treatment if feasible. Arms were well balanced according to age, sex, clinical stage and performance status. Ten patients from arm A and 13 from arm B had PS 2 or 3; 14 patients from arm A and 8 from arm B had clinically significant antecedent and/or concomitant disease (SACD: cardiac, vascular, cerebrovascular, neurological, renal or other). On the intent-to-treat basis, the results were the following. ARM A: median number of cycles 3 (range 1--6); early death 3 patients; 16/27 responses (59%), 7 complete (30%). ARM B: median number of cycles 3 (range 1-6); early death 4 patients; 12/20 responses (60%), 3 complete (15%). There was no difference either in response rate or survival between the two arms, and pooled results from the two arms displayed a plateau on the survival curve from the 20-th month onwards on the probability level of 0.40. Clinical stage of NHL, bulky disease, age and sex did not influence survival. Initial performance status did influence survival at the significance level of p = 0.045. Although presence of SACD did not influence initial performance status, it had a strong negative impact on survival p = 0.0004). The results point to the existence of two prognostic categories of elderly patients with large cell NHL, one with a poor survival, the other achieving a significant response rate and relapse free survival. Comorbidity (SACD) apparently accounts for the poor survival in a subpopulation of elderly patients. Clinical trials with elderly patients with NHL with PS 0 or 1 and no serious coexisting disease as inclusion criteria, analyzed on an evaluable patients basis, target only to a prognostically better subpopulation among these patients.

Should researchers accept funding from the tobacco industry?

Tamoxifen in cancer therapy: minireview.

Tamoxifen belongs among relatively new drugs. As it has already been shown, it undoubtedly brings a benefit to oncology patients. However, there are still questions regarding its broader use in therapy or cancer prevention. This review puts together some data available at present time with the aim of elucidating the most important aspects of its use in medical oncology.

Immunohistochemical analysis of expression of a 65 kDa oncofetal protein (p65), epidermal growth factor receptor (EGFR), oncogene c-erb B2 and tumor suppressor gene p53 protein products in breast cancer patients.

Paraffin-embedded tissue slides from 88 infiltrating ductal breast carcinoma were examined by immunohistochemistry technique with the use of monoclonal antibody against human p65 antigen and polyclonal antibody against p65-like protein present in fetal bovine serum. Immunohistochemical analysis of expression of growth factor receptors (EGFR), protein product of oncogene c-erb B2 as well as protein product of mutated anti-oncogene p53 was also done. It was established that there is no correlation between p65 and c-erbB2, EGFR or p53 expression. In low differentiated tumors (grade III) high p53 index and high EGFR and c-erbB2 expression was connected with low p65 expression. The lack of c-erbB2 and EGFR and low p53 expression was combined usually with high p65 oncoprotein levels.

Influence of estrogen, antiestrogen and UV-light on the balance between proliferation and apoptosis in MCF-7 breast adenocarcinoma cells culture.

Studies of the mechanism of actions of estrogen, antiestrogen and physical factors may provide clues to an understanding of breast cancer growth and/or regression regulation and thus identify novel targets for therapeutic intervention. Defective control of apoptosis appears to play a central role in the pathogenesis of neoplasia. Conversely, cancer therapy and ionizing radiation can induce cancer cell death by apoptosis and/or necrosis. bcl-2 gene and p-53 gene products have been both linked to programmed cell death pathways. We have analyzed the effect of estradiol, tamoxifen and UV exposure on the induction of apoptosis, expression of p53 and bcl-2 gene products as well as the proliferative activity (expressed as [3H]thymidine incorporation and PCNA and MPM2 antigens involvement) in MCF7. It has been found that estradiol increases the speed of cell cycle in MCF7 and acts as antiapoptotic factor. Tamoxifen has multiple influence on the rate of growth of cancer cells: depends on estrogen receptor (ER), conducts reduction of proliferation rate; depends on ER and other mechanisms conducts to suppressions of Bcl-2 protein expression and induction of cell death through apoptotic pathway. Estradiol prevents the apoptotic influence of tamoxifen probably by enhancement of Bcl-2 protein expression and does not prevent the inhibition of proliferation rate. The irradiation with UV induces apoptosis by over-expression of p53 and down-regulation of bcl-2 gene.

Radiation-induced apoptosis and cell cycle alterations in human carcinoma cell lines with different radiosensitivities.

Radiosensitivity of examined human neoplastic cell lines was assessed with the aid of MTT assay. Differences between radiosensitive and radioresistant human neoplastic cell lines were as follow: a) radiation-induced apoptosis detected by flow cytometry was apparent in the most radiosensitive (i.e. CH-1 ovarian carcinoma cell line), but not in the radioresistant (i.e. SKOV-3 ovarian carcinoma) cell lines, b) radiation-induced G2/M arrest appeared early after irradiation (6 hours) in both the radioresistant SKOV-3 cells and in the radiosensitive CH-1 human ovarian carcinoma cell line, but a different pattern was observed 24 hours after irradiation with 2 Gy dose with G2/M arrest only in radiosensitive cell line. The radiosensitivity and resistance to radiation-induced apoptosis in the radioresistant human breast carcinoma MDA-MB-231 cell line were similar to those observed in SKOV-3 cells. These data suggest that radiation-induced apoptosis and cell cycle alterations can predict radiosensitivity at least in some examined human malignant cells in vitro.

Effect of epinephrine and combination treatment of epinephrine and heat on melanoma cell lines. Study of cytotoxicity and kinetics of 72-kD stress protein.

To elucidate the effect of epinephrine and the combination with heat on malignant cells, using two melanoma cell lines, HM6KO and G361, we have examined the cytotoxicity and induction of 72-kD stress protein (HSP72) after the treatments. After epinephrine treatment, in both cell lines, cell survival rates decreased gradually in a concentration-dependent manner. After the combination treatment, cell survival rates decreased more than those when two treatments were done separately. The cytotoxicity of epinephrine was more enhanced in G361 than in HM6KO by heat. After epinephrine treatment, in both cell lines, the level of HSP72 did not elevate. After combination treatment, in HM6KO, the level of HSP72 were higher than those of heat alone. In G361, the kinetics of HSP72 level was similar to that of heat alone. These results suggest that epinephrine has a cytotoxicity to melanoma cells and the cytotoxicity is enhanced by the combination. In addition, it is probable that epinephrine does not have HSP72 inducibility in HM6KO and G361, and the different kinetics of HSP72 between the cell lines in the combination treatment may play an important role to determine the degree of enhancement.

Blood levels of natural antioxidants in gastric and colorectal precancerous lesions and cancers in Slovakia.

A long-term sufficient intake of fruits and vegetables reduces significantly the risk of gastric and colorectal carcinoma. It is anticipated that natural antioxidants are involved in this effect in addition to other substances. The aim of this study was to determine levels of vitamins A, C and E, as well as beta-carotene, selenium, zinc and copper in blood of 249 patients with precancerous lesions (atrophic gastritis, gastric hyperplastic polyp, gastric, colonic and rectal adenoma, chronic ulcerative colitis) and in 96 individuals with gastric, colonic or rectal carcinoma and to compare these levels with the values of a control group of 130 healthy individuals. We have found that the frequency of average values of analyzed micronutrients in precancerous groups was decreasing in the order vit C > vit E/vit A > Se > beta-car. The average levels of vitamins and beta-carotene were significantly reduced in all carcinoma groups, while selenium level showed a decrease only in the gastric carcinoma group. Copper level was elevated in the ulcerative colitis group and in all groups with carcinoma. The results indicate a frequent insufficient saturation of organism by natural antioxidants in groups with precancerous lesions and carcinomas of stomach and colorectum. Therefore, it is necessary to increase the general consumption of fruits and vegetables in Slovakia as a part of primary prevention of malignant diseases in these organs. Chemoprevention may be recommended in individuals with precancerous lesions.

Do de novo acute myeloid leukemias with normal cytogenetics involve two main prognostic categories distinguished by the presence of erythroblastic and/or megakaryocytic dysplasia?

De novo acute myeloid leukemias (AML) patients with normal cytogenetics represent a standard risk cytogenetic group. Erythroblastic and/or megakaryocytic dysplasia (EMD) in diagnostic bone marrow smears of 28 consecutive AML patients with a normal karyotype was studied. Twelve patients 21-85 (median 48) years old were categorized without EMD, 14 patients 34-90 (median 58) years old with EMD, and 2 patients were not evaluable for EMD. One cycle of induction therapy 4 + 7, with 4 doses of daunorubicin 45 mg/m2/d and standard doses of cytosine arabinoside for 7 days induced 10 complete and 2 partial remissions in 12 cases without EMD but lead to only one complete remission, 6 non-responses and 3 induction deaths in 10 cases with EMD (p = 0.002). However, high doses of cytosine arabinoside plus daunorubicin induced complete remission in 6 of 7 patients with EMD. In patients under 66 years treated by intensive consolidations the estimate of median survival was 50.6 months in 10 cases without EMD, significantly higher than 8.0 months in 11 cases with EMD (p = 0.043). De novo AML with normal cytogenetics might be divided into two biological categories, the first favorable-risk category without EMD and the second poor-risk category with EMD.

Chromosomal changes in somatic cells in seminoma patients after treatment with ionizing radiation or cytostatics.

Seminomas are sensitive to both ionizing radiation and cytostatic drugs. The study's objective was to find out the effects of cytostatics or ionizing radiation by comparing the results of genome testing before treatment and immediately afterwards. Repeat cytogenetic testing six months after completion of treatment was used to find out changes resulting from reparatory processes after various types of treatment and the degree of elimination of defective lymphocytes from circulation. Three cytogenetic tests were used in our study to find out structural changes in chromosomes (percentage of aberrations), sister chromatid exchanges (SCE) and the number of micronuclei in binuclear lymphocytes (MN). In patients treated with ionizing radiation, strong inhibition of the mitotic activity of lymphocytes occurred after irradiation of para-aortal and ipsilateral inguinal lymph nodes. However, it is difficult to make a connection between the mitotic activity of lymphocytes and their total number, which was found to be within a normal range throughout the study. There is, therefore, another possibility, i.e. that this process actually involves impairment of intracellular enzymes and blockage of the synthesis of macromolecules in lymphocytes which have suffered a large degree of genome damage. Six months after a completed course of irradiation, mitotic activity was found to be mostly normal; however, there was still a very high percentage of aberrations compared with group II (patients treated with a cytostatic, paraplatin) or with respect to the control group, in which the average percentage of aberrations was 1.42 (excluding dicentrics and rings, which are found in all irradiated patients). From the cytological-mutagenetic point of view, chemotherapy proved to be less aggressive to patients. The results of recovery were visible earlier and the elimination of damaged cells was quicker.

HDR intraluminal brachytherapy in the treatment of malignant bronchial obstructions.

Symptomatology of malignant intrabronchial obstructions has a serious negative effect on the quality of patients' life. Intrabronchial brachytherapy can play an important role in the palliation of these symptoms. Between December 1996 and September 1998 48 patients suffering from malignant intrabronchial obstructions were treated with intraluminal brachytherapy in the Dept. of Radiation Oncology at the University Maternity Hospital in Brno. Gammamed HDR automatical afterloading equipment was used to treat all patients. The first group (23 patients) was treated with a combination of intraluminal brachytherapy and external radiotherapy. The second group (18 patients who had relapsed after previous external radiotherapy) was given intraluminal radiotherapy only. A third group (7 patients) underwent intraluminal brachytherapy only. In the first group 17 patients (77%) showed symptomatic relief with tumor regression on X-ray in 16 patients and with bronchoscopic regression in 19 patients. Seven patients died before October 1998 having survived 1-6 months after the first brachytherapy application. Sixteen patients are still alive (1-14 months). In the second group, 10 patients (56%) reported significant improvement of symptoms, with endoscopic regression in 12 patients. Twelve patients died before October 1998 surviving 1-6 months after the first brachytherapy session, 6 patients are still alive 1-5 months after the first brachytherapy fraction. In the third group, bronchoscopy confirmed a complete disappearance of intrabronchial lesion in two cases with early intrabronchial tumor. Five patients reported symptomatic improvement with endoscopic regression of the tumor. There was only one complication recorded: bronchospasm in one patient. The short follow up and limited number of patients does not allow comment on the late effects and survival, yet. In conclusion, intraluminal brachytherapy is an effective and safe approach for palliation of malignant bronchial obstructions.

Synergistic cell killing by combination therapy of retinoic acid and hyperthermia in human epidermoid laryngeal carcinoma cells in culture.

In vitro monolayer culture and clonogenic assay were used to investigate the individual and combined effect of temperature and retinoic acid (RA) on cellular morphology and colony forming ability of human epidermoid laryngeal carcinoma (HEp-2) cells. 20 micromol. RA alone inhibited multilayer formation and induced cell flattening. Hyperthermia (42 degrees C) individually caused formation of cytoplasmic processes and irregularities in cellular shape and size. Combined effect of hyperthermia (42 degrees C) and 20 micromol. RA treatment caused bleb formation on cell surfaces and lysis of cytoplasmic and nuclear membrane. RA treatment also caused dose-dependent reduction of colony growth. Heat-induced cell killing was only observed at lethal temperatures of 43 degrees C and above. RA in combination with heat synergistically inhibited colony formation even at non lethal temperatures of 41 and 42 degrees C. These results indicate that RA in combination with hyperthermia may facilitate the therapy of human epidermoid larynx carcinoma.

Recent trends in cancer mortality in the Slovak Republic and in Europe.

During the last 30 years the trends in cancer mortality in Europe significantly changed. In 1970 the male and female cancer mortality (all ages) was higher in the Western Europe than in the "socialist" Central and Eastern Europe. After 1970 in most Western countries decrease or no change of male premature (0-64 years) cancer mortality was observed. The decrease was deepest in Finland and in United Kingdom. In the most of the former communist countries an increase of both total and premature male cancer mortality was observed, especially in Hungary, Poland, Roumania, Bulgaria and in some regions of the former Soviet Union. Present male premature cancer mortality in Hungary is two-times higher than the average of European Union. Male cancer mortality in the Slovak Republic is at least two-times higher than in United Kingdom, Switzerland or Sweden. These differences are partially explainable by the higher prevalence of smoking in the East. The further risk factor could be oxidative stress, caused by low intake of antioxidants and high intake of spirits. In female populations, the differences between East and West are not so dramatic, with the exception of extremely high mortality in Hungarian females. Parallel increase of female lung cancer mortality both in the West and East is caused probably by the continually increasing smoking prevalence in females almost in the whole Europe. Further local risk factors in Eastern Europe (e.g. pollution) need to be identified with more specificity for preventive programs in Eastern Europe. This region is a prospective area for the research on lesser known cancer risk factors, e.g., chronic deficiency of antioxidants, natural anticarcinogens and psychosocial disorders.

Myeloid differentiation and maturation of SCF+IL-3+IL-11 expanded AC133+/CD34+ cells selected from high-risk breast cancer patients.

The AC133 antigen is selectively expressed on subset of CD 34+ cells isolated from leukapheresis products from high risk breast cancer patients receiving chemotherapy plus G-CSF. MiniMACS AC133+ isolated cells contained a mean of 85% (80-90) AC133+ cells. Enriched AC133+ cells coexpressed 80% CD34+, 6.6% CD33+ and 2% CD15+. Separated AC133+ cells contained 600 GFU-GM/10(4) cells and 70 BFU-E/10(4) cells. Flow-cytometric analysis indicated that AC133+ cells were isolated from cells population with low granularity (SS), while CD33+ a CD15+ cells had a high granularity. After a seven-day ex vivo expansion in the presence of SCF + IL-3 + IL11, the expansion of cells increased 19.4 times. The mean percentage of blasts decreased from 100% at the start of culture to 81% on day 3 and 30% on day 7. Promyelocytes were slow to appear with 10% present on day 3, but thereafter increased to 33% on day 7. The appearance of myelocytes and metamyelocytes lagged 3 days behind promyelocytes and continued to increase during culture to become the predominant (30%) cell type on day 7. Very few neutrophils (2%) were observed in any of the cultures on day 7. Monocytes or macrophages were not detected on day 7. By day 7 megakaryocytes were present at low levels (10%). The mean value of CFU-GM in the culture after day 7 of ex vivo expansion in the presence of SCF+IL-3+IL-11 had increased 45-fold, BFU-E 5-fold. After 7 days of expansion with IL-3+SCF+IL-11 cells expressed a mean of 12% CD34+, 8% AC133+, 59% CD33+ and 30% CD15+. The aim of this experiment was to determine whether ex vivo culture of peripheral blood AC133+ cells could generate sufficient numbers of progenitors to potentially abrogate cytopenia after transplantation and passive purging of tumor cells.

Differential modulation of xenobiotic metabolizing enzymes by vanadium during diethylnitrosamine-induced hepatocarcinogenesis in Sprague-Dawley rats.

Effect of vanadium on hepatic xenobiotic biotransformation in rats exposed to diethylnitrosamine (DENA, 200 mg/kg body weight, intraperitoneally) was investigated to elucidate a possible mechanism of vanadium mediated prevention of chemical carcinogenesis. Vanadium supplementation (0.5 ppm ad libitum with drinking water), at different phases before and after DENA treatment, significantly modulated the decrease in contents of total cytochrome P-450, cytochrome b5, activity of nicotinamide adenine dinucleotide phosphate (NADPH), (reduced form) cytochrome reductase, and uridine diphospho-glucuronyl transferase (UDPGT) in microsomal fractions of whole liver, hyperplastic nodules (HNs) and non nodular surrounding parenchyma (NNSP) as induced by DENA, 20 weeks following its administration. Supplementary vanadium had also substantial influence on the activities of cytosolic enzymes, like, uridine diphospho (UDP)-glucose dehydrogenase and NAD(P)H: quinone oxidoreductase (DT-diaphorase) in the concerned tissue which were observed to be remarkably decreased as a result of DENA treatment in comparison to that of the control counterparts. However, vanadium was found to have little or no effect on the lowering ofaryl hydrocarbon hydroxylase (AHH) activity by DENA administration. On the basis of significant modulation of DENA induced alterations in cytosolic and microsomal enzyme activity it can be presumed that the chemoprotective effect of vanadium might be mediated through elevation of phase II conjugating enzymes which in turn, lead to a move and shift of metabolic profile that reduces the intracellular concentration of carcinogen derived reactive intermediates.

Characterization of factors inducing apoptosis in thymocytes of mice bearing a transplantable T-cell lymphoma of spontaneous origin.

It has been observed that the progressive ascitic growth of a transplantable T-cell lymphoma of spontaneous origin in murine host, designated as Dalton's lymphoma (DL), induces inhibition of various immune responses and is associated with an involution of thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes caused by induction of apoptosis with a decrease of CD4+CD8+, CD4+CD8- and CD4-CD8+ thymocytes. Here, we report that serum of DL-bearing mice contains soluble factors capable of inducing thymocyte apoptosis, the effectiveness of which increases with the progression of tumor growth. A decline of essential cytokines and hormones in the body due to their depletion by DL cells, which being a T-cell phenotype may have similar growth factor requirements, is ruled out by our results, suggesting additional apoptosis-inducing factors to be present in the tumor serum. Partial characterization of the serum to identify the biochemical nature of the putative serum-borne apoptosis inducing factor(s) showed that the same was proteinaceous. Further analysis of the sera of normal and DL-bearing mice by gel filtration using fast protein liquid chromatography (FPLC) and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that protein profile in the two sera differed quantitatively as well as qualitatively. FPLC analysis could resolve six peaks in both the sera, out of which the peak containing protein(s) in the range of MW 35 kD showed a higher magnitude and apoptotic activity followed by peaks containing proteins of MW in the range of 67 and 116 kD respectively as compared to that of the corresponding peaks in the normal serum. These observations were also confirmed by SDS-PAGE, with the resolution of additional proteins in the range of 25-26 kD which were found to be absent in normal serum. Further, the paper discusses different possible factors that could be associated with the progression of DL growth.

Heterogeneity of dipeptidyl peptidase IV from C6 rat glioma cells.

Dipeptidyl peptidase IV is known to be involved, due to both hydrolytic and non-hydrolytic mechanisms, in various cell functions of normal and cancer cells as well. In this report dipeptidyl peptidase IV substrate and pH preferences, some inhibition parameters, freezing/thawing sensitivity and stability against hydrolysis by trypsin were studied in C6 rat glioma cells. Our results confirmed substantial heterogeneity of dipeptidyl peptidase IV population. Such observation is important to avoid methodological artifacts and to decrease risk of misinterpretations in biological studies.

Cytotoxic activity of several unrelated drugs on L1210 mouse leukemic cell sublines with P-glycoprotein (PGP) mediated multidrug resistance (MDR) phenotype. A QSAR study.

L1210/VCR-1 and L1210/VCR-2 cell lines are multidrug resistant (MDR) sublines obtained by adaptation of mouse leukemic cell line L1210 to vincristine and, the development of MDR in these cell lines has been found to be associated with an overexpression of P-glycoprotein (PGP). In the present work we studied the relationship between the structure of 15 cytotoxic active substances (drugs) and their cytotoxicities on L1210/VCR-1 and L1210/VCR-2 resistant cell lines. The resistance of these MDR cells to the respective drugs was expressed as the ratio of IC50 values obtained for resistant and sensitive cells. These values of resistance were correlated with the following physico-chemical constants of the test substances: binding energy, Ebind; total energy of the molecule, Esum; aromaticity, Kpi; molecular weight, Mw; acidobasic constant, pKa; partition coefficient in water/octanol two phase system, log(p). It has been found that according to the cytotoxic effects the tested drugs may be divided into three groups: (i) drugs with higher cytotoxicity to the resistant cell lines as to sensitive cells (collateral hypersensitivity); (ii) drugs exhibiting approximately similar effects on sensitive and resistant cell lines; (iii) drugs with weaker cytotoxicity to resistant cells than to sensitive cells. No direct correlations with any physico-chemical constant described above could be established for cell resistance to the drug studied. However, resistance values could be fitted by multiple exponential regression with all described physico-chemical constants implied as six independent variables. The latter procedure made us to conclude that the ability of a drug to be a substrate for PGP is connected with its fulfilling the following criteria: (i) flexible structure of its molecule; (ii) molecular weight lower than approximately 1,300 g/mol; (iii) nonprotonized character at pH 7.0.

Content of epidermal growth factor receptor in metastatic breast cancer: its role in endocrine sensitivity prediction.

Epidermal growth factor receptor (EGF-R) is known as an indicator of endocrine independence of breast cancer. However, a small proportion of EGF-R expressing tumors was found to respond to endocrine treatments. On the other side, a cut-off point of EGF-R positivity is not yet defined. In the aim to find out whether there exists a cut-off value that sharply discriminate the endocrine sensitive and endocrine insensitive breast cancers, the quantitative EGF-R content was analyzed in a group of 42 female patients with metastatic disease, being routinely treated with chemo-, chemo-endocrine, or endocrine therapy alone. Steroid receptors (SR) and EGF-R were determined by biochemical methods in tissue samples of an unselected group of patients. Patients with metastatic disease, either at diagnosis, or developed after the treatment of operable or locally advanced breast cancer, were included in the present analysis. According to the treatments used, and their therapeutic response, all patients were divided in endocrine sensitive or resistant, and chemo-sensitive or resistant. The SR and EGF-R status and content was analyzed in relation to the sensitivity to both systemic treatments. The EGF-R content was significantly lower in responders to endocrine treatments, compared to non-responders, while there was no difference in EGF-R level, in relation to the sensitivity to chemotherapy. In addition, the EGF-R content was significantly higher in chemo-sensitive tumors, than in endocrine sensitive. On the contrary, ER content was significantly higher in endocrine sensitive, than in endocrine resistant, and in chemo sensitive patients, as well. Similar differences were found in PR content, but they were less pronounced. While the individual ER contents in endocrine sensitive and endocrine resistant tumors overlapped, the EGF-R ranges were different: no one endocrine sensitive tumor exceeded the EGF-R content of 26 fmol/mg, thus suggesting the EGF-R cut-off point of endocrine sensitivity. The clinical use of EGF-R, with the cut-off point of 26 fmol/mg, in addition to clinical criteria of endocrine sensitivity and SRs, would significantly improve the correct endocrine sensitivity prediction (from 52 to 78%). In conclusion, in a group of metastatic breast cancer patients, treated routinely by systemic therapies it was found, that the use of higher cut-off point for EGF-R positivity can improve the prediction of endocrine sensitivity. The prognostic relevance of this cut-off value remains to be analyzed.

A fraction isolated from Ehrlich ascites carcinoma as an antitumor and differentiating agent against human leukemic cell ML-2.

Lipopolysaccharide fraction isolated from Ehrlich ascites carcinoma (E-LPS) was investigated as an antitumor agent against human leukemia cell ML-2. Marked cell growth inhibition was observed with ML-2 cell accompanied by inhibition of DNA synthesis and perturbation of cell cycle. Induction of differentiation in treated ML-2 cells was observed as indicated by morphological maturation, NBT reducing activity and indirect immunofluorescence.

Electrophoretic characterization of a gamma-1-heavy chain disease.

This report describes a new case of gamma-1-heavy chain disease found in a woman with malignant lymphoproliferative disease. The patient's serum and urine containing gamma-1-heavy chains were analyzed using different electrophoretic approaches, especially two-dimensional electrophoresis and immunoblotting analysis. In a serum sample, five sets of gamma-1-heavy chain spots differing in molecular weight with acidic pI values and one set of more basic gamma-1-heavy chain spots were found. The major group of spots exhibited molecular weight in the range from 29 to 39 kDa. Examination of urine sample proved the presence of the more basic set of gamma-1-heavy chain spots and two acidic groups, including 29 to 39 kDa set.

Paraquat-induced lipid peroxidation and injury in Ehrlich ascites tumor cells.

The participation of lipid peroxidation products in the mechanisms of paraquat toxicity in Ehrlich ascites tumor (EAT) cells was observed. Paraquat in a concentration 0.5-1.0 mmol increased the level of lipid peroxidation according to the Ohakawa TBARS (thiobarbituric acid-reactive substances) method. These changes in TBARS production in EAT cells correlated with paraquat toxicity on the cells registered by using the method for cell injury, which is based on changes in lactate dehydrogenase activity. The metal chelator DTA removed the effect of paraquat on TBARS production and on cell injury. The present data suggested that the increased level of lipid peroxidation and cell injury is a result of the paraquat action in EAT cells depending on iron.

Hematological and cytogenetic response of interferon alpha 2b alone and combined interferon alpha plus cytarabine as a first-line treatment in chronic myeloid leukemia.

Treatment with interferon-alpha (IFNalpha) prolongs survival in chronic myeloid leukemia (CML). Additionally, cytarabine (AraC) can reduce the number of Ph + metaphases. Fortythree previously untreated patients with CML in chronic phase were randomly assigned to receive either. IFNalpha 2b (5 MU sqm/daily) or IFNalpha 2b in the same dosages plus monthly courses of low-dose AraC. The aim were complete hematologic remission at 6 months and cytogenetic response at 12 months. A complete hematologic remission occurred in 60.4% patients with single IFNalpha 2b in 76.2% patients with combination therapy. A cytogenetic response was present in 13.9% (major in 2 patients) with IFN therapy and in 38.1% patients with combination therapy. Two of 21 patients treated with IFNalpha/AraC therapy achieved major (9.52%), 4 partial (19.04%) and 2 minor (9.52%) cytogenetic response. Major side effects were cytopenia (20.1%), flu-like syndromes (42.4%) and increase of hepatic transaminases (3.4%). The side effects were more significant in the group receiving combination therapy. Based on published data that show a survival advantage for patients who achieved any cytogenetic response, and high rate of cytogenetic response which we observed in our study we believe that IFN plus AraC regimen could be a front-line therapy for CML.

Radiotherapy of early stages Hodgkin's disease. 10 years experience of the Masaryk Memorial Cancer Institute.

Radiotherapy and chemotherapy, alone or in combination, are curative treatment methods in early stages of Hodgkin's disease (HD). The choice of treatment depends on the stage of the disease, histological type and localization of the tumor, as well as on other prognostic factors. A retrospective study was conducted including 145 patients with clinical Stages I and II of HD according to Ann Arbor classification, all treated in the Masaryk Memorial Cancer Institute in Brno during the years 1985 through 1994. 80 patients were males (55%) and 65 patients females (45%). The age of the patients ranged from 11 to 77 years, with an average of 34.8 years. 41 patients were diagnosed with Stage IA tumor, 1 patient with Stage IB, 75 patients with Stage IIA and 28 with Stage IIB disease. The histological types of the disease were lymphocyte predominant in 23 patients, nodular sclerosis in 49 patients, mixed cellularity in 65 cases and lymphocyte depletion in 8 cases. 91 patients were treated with radiotherapy alone. In this group 14 patients relapsed within the radiation field (15%) and 25 outside the radiation field (28%). 39 patients were treated with combination of radiotherapy and chemotherapy. In this group relapse occurred within the radiation field in 3 patients (8%) and outside the radiation field in 7 patients (18%). 15 patients were given chemotherapy alone, 7 patients from this group experienced a relapse. The five-year survival was 81% in patients with Stages IA and IIA disease, 65% in Stages IB and IIB disease. The five-year survival in the patients who relapsed was 56%. Radiotherapy remains the curative method of choice in highly selected group of patients with early stages of Hodgkin's disease. The results of radiotherapy alone are unsatisfactory in unselected clinical Stage I--II patients because of the presence of patients with adverse prognostic factors, particularly B symptomatology, mixed cellularity/lymphocyte depletion histology, higher age. These patients are candidates for combined treatment. Modern equipment and meticulous treatment are conditions crucial for the outcome of curative radiotherapy in patients with Hodgkin's disease. Combination chemotherapy is very effective in the treatment of relapse following the primary radiotherapy.

The impact of delivered dose errors on local control of irradiated advanced laryngeal cancer.

On the basis of 1,015 entrance and 863 exit dose in vivo measurements, 863 calculations of midline dose were done, and the average deviation and ranges of its value were estimated. Data of 710 advanced larynx cancers were reviewed in order to achieve dose-response relationship. Patients data were fitted directly to L-Q model using maximum likelihood estimation. In 16.5% of measurements the deviation of midline dose was larger than -5.2%. A steep dose response relationship for TCP was found. Considering -5.2% deviation of 2 Gy fraction and 72 Gy of total dose, the 17% (from 48 to 31%) decrease of TCP was found. It shows that deviations of delivered dose influence the tumor control probability and that after systematic error finding during fractionated radiotherapy the value of remaining fraction size and total dose should be modified to compensate the change of TCP.

The role of chemotherapy in prostate cancer. Minireview.

Hormonal therapy in disseminated prostate cancer is effective in 70-80% of patients and prolongs their lives of a mean 1-2 years. Sooner or later, androgen independence develops due to a multifactorial mechanism. A smaller part of patients may respond to second-line hormonal manipulations (antiandrogen withdrawal, adrenal enzymes synthesis inhibitors, corticosteroids). In hormone-refractory disease only about 30% of patients would respond to chemotherapy. In the standard chemotherapy the mostly used cytotoxic agents are anthracyclines, platinum derivatives, vinca alkaloids and cyclophosphamide. However, combined chemotherapy is not more effective than monotherapy. Conventional chemotherapy may improve especially the quality of life. The median survival in chemotherapy patients (6-12 months) is not significantly longer when compared with the best supportive care. In recent years the main concern has been focused on new cytotoxic drugs and different combinations with hormonal agents. In Phase II studies the combinations of estramustine with oral etoposide, estramustine with taxanes and alternating weekly regimens (doxorubicin, ketoconazole/estramustine, vinblastine) show higher response rates (53-69% of patients with prostate-specific antigen decline of more than 50%) and longer survival (13-19 months) than conventional chemotherapy.

Retrovirus vector containing wild type p53 gene and its effect on human glioma cells.

A retroviral vector containing wild-type p53 tumor suppressor gene (wt-p53) under the control of viral LTR sequences was constructed and transfected into packaging cell line GP+envAm12. Virus producing single cell clone GP+envAm12/ p53clC8 (8 x 10(5) cfu/ml, determined on NIH 3T3 cells) was isolated and used to transfer wt-p53 gene into human glioma cell lines in vitro. Decreased viability in p53-infected cells as compared to uninfected or empty virus infected cells was observed.

Constitutive ubiquitination and degradation of c-myb by the 26S proteasome during proliferation and differentiation of myeloid cells.

Steady state levels of transcription factors play an important role in proliferation and differentiation of hematopoietic cells. The transcription factor c-Myb is frequently activated by retrovirus integration in murine and avian leukemias. Its deregulation has been also implicated in human acute and chronic leukemias and some other nonhematopoietic tumors. It is a short-lived protein, which is rapidly degraded by the 26S proteasome. Truncation at the carboxyl (COOH) terminus, which has occurred in some oncogenic forms ofc-Myb, results in the increased resistance to proteolysis. This stabilization correlates in vitro with less efficient ubiquitination. Here, we report the first evidence of post-translational modification of c-Myb by ubiquitin in vivo using HA-labeled ubiquitin. We also show that, in contrast to the unstable wild type or amino (NH2)-terminally truncated c-Myb form, stable carboxyl (COOH)-terminally truncated c-Myb is not targeted to degradation by covalent attachment of ubiquitin in vivo. In addition, following an analysis of subcellular fractionation of proteins from cells treated with a 26S proteasome inhibitor we were able to localize c-Myb exclusively in the nuclear compartment, suggesting the absence of a requirement for export to cytoplasm prior proteolytic processing. Furthermore, pulse-chase experiments of c-Myb protein isolated from interphase cells or cells synchronized in the G2/M or G1 phases of cell cycle did not reveal substantial cell cycle dependent differences in proteolytic processing by the 26S proteasome. Also, the demonstration that the half-life of c-Myb in myeloid progenitor M1 cells induced to differentiate along the monocytic pathway is the same as in undifferentiated cells suggested that proteolytic breakdown of c-Myb is a constitutive process during proliferation and differentiation.

Approaches to identification of HNPCC suspected patients in Slovak population.

Patients with hereditary non-polyposis colorectal cancer (HNPCC) have a DNA mismatch repair defect (MMR) in their tumor tissue that results in instability of microsatellite DNA sequences (MSI). Thus, MSI analysis may effectively indicate this form of cancer that should be then proved by analysis of germline mutations in MMR genes. The aim of this study was to identify HNPCC suspected patients in the Slovak population by investigating microsatellite instability in colorectal tumor tissues. MSI was studied at 5-11 loci in matched tumor and normal DNA using radioactively labeled PCR products separated on sequencing gels. High microsatellite instability (MSI-H) was present only in patients younger than 50 years, in 100% of patients having two affected relatives by colorectal cancer and in 67% of patients with only one affected relative. In both groups of patients colorectal cancer was present in two successive generations. No MSI-H was found in the group of patients older than 50 years, even if they had positive family history for colorectal cancer. Among all markers used, the BAT26 mononucleotide repeat (100%), DI0S197 and D13S175 (62.5%) dinucleotide repeats were the most frequently altered in the tumor tissues. Retrospective analysis revealed that some of the patients having MSI-H tumors have had clinicopathological characteristics frequently reported to HNPCC. The family members of those patients with MSI-H are enrolled in preventive health care program until mutational analyses will enable to select carriers from non-carriers of mutated MMR genes.