VHL and HIF-1α: gene variations and prognosis in early-stage clear cell renal cell carcinoma.

Von Hipple-Lindau gene (VHL) inactivation represents the most frequent abnormality in clear cell renal cell carcinoma (ccRCC). Hypoxia-inducible factor-1α (HIF-1α) expression is regulated by O2 level. In normal O2 conditions, VHL binds HIF-1α and allows HIF-1α proteasomal degradation. A single-nucleotide polymorphism (SNP) has been found located in the oxygen-dependent degradation domain at codon 582 (C1772T, rs11549465, Pro582Ser). In hypoxia, VHL/HIF-1α interaction is abolished and HIF-1α activates target genes in the nucleus. This study analyzes the impact of genetic alterations and protein expression of VHL and the C1772T SNP of HIF-1α gene (HIF-1α) on prognosis in early-stage ccRCC (pT1a, pT1b, and pT2). Mutational analysis of the entire VHL sequence and the genotyping of HIF-1α C1772T SNP were performed together with VHL promoter methylation analysis and loss of heterozygosis (LOH) analysis at (3p25) locus. Data obtained were correlated with VHL and HIF-1α protein expression and with tumor-specific survival (TSS). VHL mutations, methylation status, and LOH were detected in 51, 11, and 12% of cases, respectively. Our results support the association between biallelic alterations and/or VHL silencing with a worse TSS. Moreover, we found a significant association between the HIF-1α C1772C genotype and a worse TSS. The same association was found when testing the presence of HIF-1α protein in the nucleus. Our results highlight the role of VHL/HIF-1α pathway in RCC and support the molecular heterogeneity of early-stage ccRCC. More important, we show the involvement of HIF-1α C1772T SNP in ccRCC progression.

PIK3CA in breast carcinoma: a mutational analysis of sporadic and hereditary cases.

The PI3K-Akt cascade is a key signaling pathway involved in cell proliferation, survival, and growth. Activating PIK3CA mutations have been reported in breast carcinoma (BC). The aim of this study was to characterize the PIK3CA mutations at exons 9 and 20 in a series of 176 sporadic and 22 hereditary BCs and to correlate the results with clinicopathologic parameters and survival. In sporadic BC, 68 missense mutations were detected. PIK3CA mutations were significantly associated with ER+ in HER2-negative cases. A higher frequency of PIK3CA mutations was present in lobular carcinoma compared with ductal carcinoma (50% vs. 35%). There was no association between the survival and PIK3CA mutational status. In hereditary BC, PIK3CA mutations were found only in the BRCA2 group. The PIK3CA mutation seems to characterize the luminal-type BC, in both sporadic and BRCA2 mutated forms, and is absent in the basal-type BC, in both the sporadic and BRCA1 mutated forms.

Dysregulated PI3K/Akt/PTEN pathway is a marker of a short disease-free survival in node-negative breast carcinoma.

The phosphoinositide 3-kinase/Akt pathway is involved in the pathogenesis of several human cancers. In this study, the biological and prognostic value of phosphoinositide 3-kinase/Akt pathway dysregulation was assessed by immunohistochemistry in a well-characterized series of 72 patients with node-negative breast cancer with a long-term follow-up. Phosphorylated Akt and PTEN expression was reduced in 32% and 12.5% of the tumors, respectively. Phosphorylated Akt or PTEN status was not associated with the main clinicopathologic and biological parameters, whereas their expression was tightly related to their downstream targets cyclin D1 and p27(Kip1) which are involved in cell proliferation. Survival analysis showed a strong association between a shorter disease-free survival and the dysregulated expression of phosphorylated Akt (P = .036), PTEN (P = .003), p27(Kip1) (P = .008), and Ki67 (P = .0007), or the distinct subtypes of breast tumors (luminal, HER2 overexpressing, and basal-like; P = .03). Moreover, multivariate analysis using the Cox proportional-hazards regression model showed that PTEN and Ki67 were independent predictive factors of disease recurrence and that their simultaneous dysregulation strongly increased the hazards ratio of the patients with node-negative breast cancer (hazards ratio, 38.30; P = .0014). In conclusion, our results show that the dysregulation of the phosphoinositide 3-kinase/Akt/PTEN pathway is relevant to the prognosis in node-negative breast carcinoma and that the evaluation of key components of this pathway might be a useful tool to identify the patients with node-negative breast cancer at high-risk of disease recurrence.

Cyclin E correlates with manganese superoxide dismutase expression and predicts survival in early breast cancer patients receiving adjuvant epirubicin-based chemotherapy.

Anthracycline-based chemotherapy represents a milestone in the treatment of breast cancer. We previously demonstrated in an in vitro model that cyclin E overexpression is associated with increased expression of manganese superoxide dismutase (MnSOD) and resistance to doxorubicin. In the present study, immunohistochemical expression of cyclin E and MnSOD was evaluated in 134 early breast cancer patients receiving adjuvant epirubicin-based chemotherapy regimens containing epirubicin. Both parameters were correlated with the available clinicopathological parameters and with the outcome of patients. Overexpression of cyclin E and MnSOD was detected in 46 (34.3%) and 56 (41.8%) patients, respectively, and expression levels of the two proteins were related. Disease-free and alive patients displayed a lower mean percentage of cyclin E-expressing cells than relapsed and dead patients, respectively. Kaplan-Meier survival analysis demonstrated a significant separation between high versus low cyclin E-expressing tumors in terms of overall survival (P = 0.038 by log-rank). Similar results were obtained considering the subset of node-negative patients separately. No significant relationship with patient outcome was observed for MnSOD expression levels. At multivariate analysis cyclin E failed to demonstrate an independent prognostic value. In conclusion, the results of the present study support previous evidence that increased cyclin E expression is associated with higher MnSOD expression levels and poorer outcome, at least as evaluated in terms of overall survival. Further studies are warranted to evaluate the usefulness of cyclin E as a prognostic marker to identify breast cancer patients at higher risk of death from the disease when treated with adjuvant anthracycline-based therapy.

Establishment and characterization of 4 new human pancreatic cancer cell lines: evidences of different tumor phenotypes.

OBJECTIVES: Pancreatic cancer still remains a challenge for its biological complexity and lack of effective therapeutic strategies. Establishing new pancreatic cancer cell lines is therefore of paramount importance to clarify its biology. METHODS: We established and characterized 4 new pancreatic cancer cell lines (PP78, PP109, PP117, and PP161) according to their genetic (K-Ras, TP53, CDKN2A, and MADH4; DNA fingerprinting; karyotype), cytostructural (cytokeratins 7, 8, 18, and 19 vimentin, and ezrin), and functional profiles (doubling time; migration assay). RESULTS: K-Ras, TP53, and CDKN2A gene alterations were detected in all 4 of them. Each cell line had a unique DNA profile revealed by DNA fingerprinting. A complex karyotype with numerous structural and numeric chromosomal abnormalities was present in each cell line. All 4 cell lines showed positivity for cytokeratins 7, 8, and 18. All but PP78 expressed cytokeratin 19, whereas vimentin was expressed only in PP117 and PP78 cells. A different ezrin cellular distribution was noticed in PP78 and PP117, being mostly located at membrane ruffles. This peculiar distribution was associated with the strongest migratory capability. CONCLUSIONS: Our results seem to confirm the pancreatic ductal adenocarcinoma heterogeneity; in fact, the same genetic abnormalities (K-Ras, TP53, and CDKN2A) may have different effects on tumor biology depending on cellular differentiation.

Nuclear expression of hypoxia-inducible factor-1alpha in clear cell renal cell carcinoma is involved in tumor progression.

OBJECTIVES: The most frequent genomic abnormality in clear cell renal cell carcinoma (cc-RCC) is inactivation of Von Hippel-Lindau gene (VHL). pVHL19 is a ligase promoting proteosomal degradation of hypoxia-inducible factor-1alpha (HIF-1alpha); pVHL30 is associated with microtubules. VHL exert its oncogenetic action both directly and through HIF-1alpha activation. TNM classification is unable to define a correct prognostic evaluation of intracapsular cc-RCC. The nucleo-cytoplasmic trafficking in VHL/HIF-1alpha pathway could be relevant in understanding the molecular pathogenesis of renal carcinogenesis. This study analyzes VHL/HIF-1alpha proteins in a large series of intracapsular cc-RCCs, correlating their expression and cellular localization with prognosis. MATERIALS AND METHODS: Two anti-pVHL (clones Ig32 and Ig33) and 1 anti-HIF-1alpha were used on tissue microarrays from 136 intracapsular cc-RCCs (mean follow-up: 74 mo). Clone 32 recognizes both pVHLs, whereas clone 33 only pVHL30. Results were matched with clinicopathologic variables and tumor-specific survival (TSS). RESULTS: A strong cytoplasmic positivity was found for all antibodies in the largest part of cases, associated to a strong nuclear localization in the case of HIF-1alpha. All pVHL-negative cases were associated with high HIF-1alpha expression. pVHL negativity and HIF-1alpha nuclear positivity significantly correlated with shorter TSS. In multivariate analysis both pVHL negativity and HIF-1alpha nuclear expression were independent predictors of TSS. CONCLUSIONS: The localization of the proteins well matches with their role and with the supposed tumor molecular pathways. The correlation with prognosis of VHL/HIF-1alpha alterations confirms the relevance of their molecular pathway and of the cellular trafficking of their products in the pathogenesis of renal cancer.

A fast method to detect cell surface expression of thyrotropin receptor (TSHr): the microchip flow cytometry analysis.

Loss-of-function mutations of the thyrotropin receptor (TSHr) may be responsible for congenital hypothyroidism or isolated hyperthyreotropinemia. To study cell surface expression of inactivating TSHr mutations detected in patients with isolated hyperthyreotropinemia (L252P, Q8fsX62, P27T, E34K, R46P, D403N, W488R, and M527T), we used the Agilent 2100 bioanalyzer to perform microchip flow cytometry analysis. The previously described TSHr inactivating mutation T477I was used as control. The level of receptor expression in COS-7 cells transfected with the T477I measured by binding assay was four times lower with respect to the wild-type TSHr. The very low expression of T477I was confirmed by fluorescence-activated cell sorting (FACS) analysis and by microchip flow cytometry analysis, suggesting that this method can be a reliable system to measure receptor cell surface expression. Other inactivating TSHr mutations were expressed in COS-7 cells for binding studies, FACS analysis, and microchip flow cytometry analysis. Binding studies showed that L252P, Q8fsX62, P27T, E34K, R46P, D403N, W488R, and M527T mutants had a low expression at the cell surface, as demonstrated by Bmax values. Data obtained by binding studies were in good agreement with data obtained by FACS analysis and microchip flow cytometry analysis. In conclusion, the low number of cells required for analysis and the ease of use make the microchip flow cytometry analysis a very reliable and favorable system to study cell surface expression of TSHr mutations.

High level of messenger RNA for BRMS1 in primary breast carcinomas is associated with poor prognosis.

BRMS1 is regarded as a metastasis suppressor gene for its ability to reduce metastatic potential of human and murine breast cancer cells as well as human melanoma cells. However, BRMS1 association to human tumor progression is not clearly understood. In the present study we analyzed BRMS1 mRNA expression in tumor progression and its potential prognostic value for breast carcinoma. BRMS1 mRNA expression level was quantified by real-time PCR in 47 tumoral, in 14 peritumoral and in 15 metastatic microdissected cellular populations from 47 breast cancer patients with 10-year follow up. We found BRMS1 expression to be higher in carcinoma cells than in matching normal epithelial cell populations in 10 out of 14 cases (p = 0.0005), while lymph-nodal carcinoma cells showed lower BRMS1 expression in 9 out of 15 cases (p = 0.001). Using both in vivo (human mammary breast carcinomas) and in vitro systems (breast cancer cell lines) we were able to demonstrate that BRMS1 overexpression was not a bias effect induced by cell proliferation rate. BRMS1 expression levels did not correlate with standard breast cancer prognostic factors but BRMS1 higher expression was associated with patient shorter disease-free and overall survival. Our findings are apparently inconsistent with the concept of BRMS1 as a metastasis suppressor gene. One possible explanation is that epithelial cells increase their BRMS1 expression as a compensatory response to tumor formation or metastasis progression, which is elevated in proportion to tumor aggressiveness, whereas those cells of the primary tumor that cannot upregulate BRMS1 escape to form metastasis.

Cyclin A and E2F1 overexpression correlate with reduced disease-free survival in node-negative breast cancer patients.

BACKGROUND: Available prognostic factors do not accurately identify node-negative breast cancer patients at high risk of disease recurrence and progression. PATIENTS AND METHODS: Cyclin A and E2F1 expression levels were evaluated in 75 consecutive node-negative breast cancer patients with a median follow-up of 10 years. Both parameters were tested for correlation with all the available clinicopathological parameters and with the clinical evolution of the disease. RESULTS: Cyclin A was overexprNed in 45.3% of patients and significantly related to large tumor size, high Ki67 and high E2F1 expression levels. No relationship was observed between cyclin A and tumor estrogen receptor (ER) status, grading or patient age. Seventeen patients relapsed within 5 years from diagnosis. Twelve (71%) of them showed cyclin A overexpression in comparison with 22 (38%) out of the 58 who did not relapse (p = 0.02). Disease-free survival (DFS) was significantly shorter in patients with cyclin A-overexpressing tumors compared to non-overexpressing ones (p = 0.01). DFS was also significantly longer in low vs. high Ki67 expression (p = 0.003) and in low vs. high E2F1 expression (p = 0.02). On multivariate analysis, the simultaneous high expression of all three parameters (cyclin A, Ki67 and E2Fl) was a strong independent prognostic factor for shorter DFS (HR 13.4). CONCLUSION: These findings suggest that assessment of cyclin A and/or E2F1 expression levels, associated with Ki67, might be useful for a better prognostic evaluation of node-negative breast cancer patients and support the need for further studies to evaluate their suitability for use in the routine clinical management of these patients.

Intracapsular clear cell renal carcinoma: ploidy status improves the prognostic value of the 2002 TNM classification.

PURPOSES: The TNM classification has been revised for the 2002 edition of the UICC publication to better stratify patients with intracapsular renal cell carcinoma (RCC) but few studies have been published to date to validate this new classification. Moreover, additional prognostic factors seem to be necessary to improve the prediction of intracapsular tumor aggressiveness and the definition of patient subgroups at high risk for metastases. We report the long-term results of the new TNM scheme. We evaluated the impact of DNA content, S-phase and MIB-1 (Dako, Glostrup, Denmark) score. MATERIALS AND METHODS: A total of 136 patients with intracapsular clear cell RCC and a mean followup of 74 months were reclassified. Tumor specific survival (TSS) was compared with nuclear grade (NG), DNA content and proliferative status (S-phase fraction and MIB-1 score). RESULTS: TSS was 92%, 81.1% and 40.1% for pT1a, pT1b and pT2, respectively (p <0.05). TSS according to DNA ploidy status (diploid vs aneuploid) was pT1a-95.2% vs 68.6% (p <0.05), pT1b-90% vs 46.7% (p <0.05) and pT2-49.2% vs 25% (p not significant). DNA ploidy was also significantly associated with survival when adjusted for NG. There was no significant association between TSS and MIB-1 score or tumor S-phase fraction. CONCLUSIONS: The 2002 TNM classification is a useful prognostic factor for evaluating organ confined RCC of the clear cell subtype. Evaluation of the DNA content in clear cell RCC appears to significantly improve the predictive value of the TNM staging system, especially in the pT1a and pT1b categories. Fuhrman NG alone or combined should be routinely used in such patients.

All-trans-retinoic acid treatment inhibits the growth of retinoic acid receptor beta messenger ribonucleic acid expressing thyroid cancer cell lines but does not reinduce the expression of thyroid-specific genes.

Conventional chemotherapy and radiotherapy are ineffective for the treatment of advanced thyroid tumors like poorly differentiated papillary, anaplastic, and medullary thyroid cancer. In the attempt to evaluate the possibility of using retinoic acid (RA) in the treatment of thyroid cancer refractory to conventional therapy, we studied the effect of all-trans-RA treatment on five human thyroid cancer cell lines. We found that WRO and NPA, derived from follicular and poorly differentiated human thyroid carcinoma, respectively, showed a growth inhibition after 25 and 21 d of RA treatment. Both apoptosis and a decrease in DNA synthesis were observed as mechanisms of growth inhibition. In the NPA cell line, a delay of cell-cycle progression has also been observed. On the contrary, we did not observe any recovery of mRNA expression of thyroid-specific genes and in particular of the sodium iodide symporter gene. The lack of recovery of radioiodide uptake after all-trans-RA treatment confirmed the inability to reexpress sodium iodide symporter mRNA. The main difference between the all-trans-RA responding cells (WRO and NPA) and the nonresponding cells [ARO, FRO (derived from human anaplastic thyroid tumors) and TT (derived from human medullary thyroid tumor)] was the basal and all-trans-RA induced RA receptor (RAR)beta mRNA expression. Interestingly, 14 thyroid tumors (10 papillary and four anaplastic) showed a significant lower expression of RARbeta mRNA when compared with normal thyroid tissues. In agreement with this result, only 30% of papillary thyroid carcinomas analyzed were positive for RARbeta protein expression with a degree of expression that was much lower than that found in normal thyroid tissue. In conclusion we found that all-trans-RA treatment can determine a significant in vitro growth inhibition especially in differentiated thyroid tumor-derived cell lines but it seems unable to reinduce the expression of thyroid-specific genes and in particular to reinduce the ability to take up iodine. The growth inhibition is likely due to apoptosis in an early phase and to a decrease of DNA synthesis later. In some cases, a delay of the cell-cycle progression also may be responsible for the growth inhibition. The finding of a basal and RA-induced RARbeta mRNA expression only in cell lines responding to all-trans-RA suggests that the growth inhibition might be mediated by RARbeta.

Long-term results of combined-modality therapy for inflammatory breast carcinoma.

Sixty-eight patients with inflammatory breast carcinoma (IBC) received treatment in 2 prospective randomized trials of multimodality therapy for locally advanced breast cancer. The treatment plan consisted of 3 courses of neoadjuvant chemotherapy with CAF (cyclophosphamide/doxorubicin/5-fluorouracil [5-FU]) or CEF (cyclophosphamide/epirubicin/5-FU) followed by surgery and 6 adjuvant courses of CAF or CEF alternated with CMF (cyclophosphamide/methotrexate/5-FU). Radiation therapy was administered at the end of adjuvant treatment. All patients with estrogen receptor-positive tumors received tamoxifen 20 mg daily for 5 years. The response rate to induction chemotherapy was 73.6% (95% CI, 61.4%-83.5%): 4 of 68 patients (6%) exhibited a pathologic remission of primary breast tumor (persistent disease in the axilla), and 2 patients (3%) exhibited a pathologic complete response. Median follow-up was 10 years (range, 5 months to 14.7 years). Disease-free survival (DFS) rates at 5 and 10 years were 29% and 20%, respectively, and median DFS was 2.2 years (range, 3.8 months to 11.5 years). Overall survival (OS) rates at 5 and 10 years were 44% and 32%, respectively, and median OS was 4 years (range, 5 months to 14.7 years). Significant prognostic factors for DFS and OS were the number of axillary nodes and residual disease in the breast at surgery. This analysis confirmed that patients with IBC obtained significant long-term survival benefit from combined-modality therapy.

Clinicopathological significance of GADD45 gene alterations in human familial breast carcinoma.

GADD45 is a DNA damage responsive gene, induced following BRCA1 expression. Mutations at GADD45 might substitute for p53 alterations in hereditary breast tumours characterized by wild-type p53. We analyzed GADD45 alterations in 59 (15 BRCA-associated) familial breast carcinomas. No mutations were found. LOH at GADD45 locus was identified in 19/59 tumours. GADD45 does not appear to be a frequent mutational target in hereditary breast cancer.

Proper targeting and activity of a nonfunctioning thyroid-stimulating hormone receptor (TSHr) combining an inactivating and activating TSHr mutation in one receptor.

Activating mutations of the thyroid-stimulating hormone receptor (TSHr) have been identified as a cause of toxic adenomas. Germline-inactivating TSHr mutations have been described as a cause of congenital hypothyroidism. The effects of combining activating and inactivating mutations within a single receptor was studied. The double mutant T477I/P639S contained an activating TSHr mutation (P639S) together with an inactivating one (T477I). The other one (I486M/P639S) contained two activating mutations. Constructs were expressed in COS-7 cells and basal and TSH-stimulated cyclic AMP (cAMP) accumulation and inositol phosphate (IP) production were determined. The expression at the cell surface was studied both with binding and fluorescence-activated cell scanning analysis. Our results show that the effect of combining the two activating mutations is an increase in the constitutive activity only for the cAMP pathway and not for the IP pathway suggesting that different mutations result in receptor conformations with different relative abilities to couple to Gs-alpha or Gq-alpha. Surprisingly the double mutant containing the T477I behaves as an activating receptor with constitutive activity both for the cAMP and IP pathways. These data show that an inactive form of the TSHr which is trapped inside a cell after transfection is able to gain the membrane surface when combined with an activated form of the receptor.

2'-Deoxyadenosine causes apoptotic cell death in a human colon carcinoma cell line.

The combination of 2'-deoxyadenosine and 2'-deoxycoformycin is toxic for the human colon carcinoma cell line LoVo. In this study we investigated the mode of action of the two compounds and have found that they promote apoptosis. The examination by fluorescence microscopy of the cells treated with the combination revealed the characteristic morphology associated with apoptosis, such as chromatin condensation and nuclear fragmentation. The occurrence of apoptosis was also confirmed by the release of cytochrome c and the proteolytic processing of procaspase-3 in cells subjected to the treatment. To exert its triggering action on the apoptotic process, 2'-deoxyadenosine enters the cells through an equilibrative nitrobenzyl-thioinosine-insensitive carrier, and must be phosphorylated by intracellular kinases. Indeed, in the present work we demonstrate by analysis of the intracellular metabolic derivatives of 2'-deoxyadenosine that, as suggested by our previous findings, in the incubation performed with 2'-deoxyadenosine and 2'-deoxycoformycin, an appreciable amount of dATP was formed. Conversely, when also an inhibitor of adenosine kinase was added to the incubation mixture, dATP was not formed, and the toxic and apoptotic effect of the combination was completely reverted.

The stem cell factor-c-kit system and mast cells in human pancreatic cancer.

Stem cell factor (SCF) and its receptor c-kit take part in the regulation of developmental processes of mast cells, hematopoietic stem cells, and melanocytes, as well as in the growth control of human malignancies. To explore the possible role of the SCF-c-kit system and of mast cells in pancreatic cancer, the concomitant expression and distribution of the two molecules were examined in 17 normal and 26 cancerous human pancreatic tissues and in 6 cultured pancreatic cancer cell lines. Mast cell distribution was also evaluated in the same tissue samples. In addition, the effects of SCF and of the c-kit tyrosine-kinase inhibitor STI571 on the growth of the cancer cell lines and of the normal pancreatic ductal cell line TAKA-1 were assessed. SCF immunoreactivity was absent in acinar, ductal, and islet cells of the normal pancreas and faint in pancreatic cancer tissues and cell lines. In contrast, c-kit was clearly present in some normal and hyperplastic ducts of the normal pancreas, in the cancer cells of 73% of the tumor samples, and in all the cell lines tested. Mast cells, identified by tryptase and chymase immunostaining on consecutive tissue sections, showed immunoreactivity for SCF and c-kit in both normal and cancerous specimens and their number was significantly increased (p = 0.03) in pancreatic cancer compared with the normal pancreas. SCF showed a dose-dependent growth inhibitory effect on TAKA-1 cells (p < 0.001), whereas pancreatic cancer cells were resistant to the SCF-induced growth inhibition. Nonetheless, the growth of TAKA-1 cells and pancreatic cancer cells was inhibited by the c-kit tyrosine kinase inhibitor STI571. In conclusion, the SCF-c-kit system, possibly with the contribution of mast cells, may have a growth-regulating role in the normal pancreas, which is altered during malignant transformation.

Bcl2-negative MCF7 cells overexpress p53: implications for the cell cycle and sensitivity to cytotoxic drugs.

PURPOSE: Bcl2 is a mitochondrial protein endowed with cytostatic and antiapoptotic activities. In this work we studied the effects of the lack of Bcl2 in MCF7 cells. METHODS: The breast cancer cell line MCF7 (Bcl2-positive) and its derivative MCF7/50B (Bcl2-negative) were compared in terms of the level of p53 expression, doubling time and distribution of cells among the cycle phases. Sensitivities to the proapoptotic drugs cisplatinum and staurosporine were measured using a clonogenic assay and the contribution of apoptosis to cytotoxicity was determined with a mitochondrial membrane potential-sensitive dye. RESULTS: Relative to MCF7, MCF7/50B cells overexpressed p53 and slowly proliferated with a significant accumulation at G(0)/G(1) and depletion in S phase. The cytotoxicity of the DNA-damaging agent cisplatinum was decreased, while that of the protein kinase inhibitor staurosporine was increased. The induced cytotoxicity was essentially due to apoptosis and necrosis, respectively. CONCLUSIONS: These results suggest that the lack of Bcl2 accompanied by p53 overexpression affects the distribution of cells among the cell cycle phases and modifies the sensitivity to cytotoxic drugs and the type of cell death.