Cell proliferation and apoptosis with BCL-2 expression in renal cell carcinoma

Bcl-2 family of proteins as therapeutic targets in genitourinary neoplasms

INTRODUCTION

Overexpression of antiapoptotic B-cell lymphoma (Bcl-2) proteins confers the dysregulation of apoptosis and results in drug resistance in a variety of cancers, including those of the genitourinary tract. Inhibitors that target prosurvival Bcl-2 proteins are in preclinical and clinical development. The objective of this review is to assess the involvement of Bcl-2 proteins as well as the preclinical and clinical activity of Bcl-2 inhibitors under evaluation for genitourinary neoplasms.

MATERIALS AND METHODS

PubMed was used with both medical subject heading terms and free search to identify the relevant literature. Information on clinical trials was obtained using http://Clincaltrials.gov, EU Clinical Trials Register, and meeting abstracts of the American Society of Clinical Oncology.

RESULTS

To date, 2 Bcl-2 inhibitors have been evaluated in clinical trials for genitourinary tumors (oblimersen and AT-101 (R-(-)-gossypol)). Both agents demonstrated some success in early stages of development, but their clinical activity did not meet expectations. Preclinical studies are under way for other Bcl-2 inhibitors including ABT-737, HA14-1, and Bcl-2 homology 3 inhibitors.

CONCLUSION

Antiapoptotic Bcl-2 proteins are potential molecular targets in genitourinary cancers. Bcl-2 inhibitors might be effective as single agents or in combination with conventional therapies. However, the biology of the Bcl-2 family in genitourinary cancers remains poorly understood and robust preclinical studies are needed to inform clinical development. Such studies should aim to identify: (1) pharmacodynamic markers that could help guide patient selection for treatment with Bcl-2 inhibitors, and (2) optimal combinations of Bcl-2 inhibitors with other anticancer agents for future clinical investigation.

Fas expression in renal cell carcinoma accurately predicts patient survival after radical nephrectomy

OBJECTIVES

To investigate Fas, Fas ligand (FasL) and Bcl-2 expression, which are considered to be important apoptotic regulatory factors in renal cell carcinomas (RCCs).

PATIENTS AND METHODS

mRNA quantification and immunohistochemistry allowed for the determination of the expression of these three factors in surgically resected tumors from 82 patients with RCC. The correlation of protein and gene expression with more than 10 years of survival data following nephrectomy (along with clinical and pathologic parameters) was analyzed using uni- and multivariate statistical models.

RESULTS

A significantly poorer outcome was observed in patients with tumors expressing high levels of Fas mRNA in the multivariate analysis (p = 0.0002). In addition, patient survival was significantly worse in FasL mRNA-positive tumor cases when compared with FasL mRNA-negative cases (p = 0.0345). Ten cases relapsed more than 5 years after nephrectomy. Among them, the tumors of 8 cases (80%) did not express FasL mRNA. Analysis of Bcl-2 did not show statistical significance of Bcl-2 expression as a prognostic indicator.

CONCLUSIONS

The data suggest that pronounced Fas expression is a surrogate biomarker of active cancer cell proliferation. Given the FasL tumor counterattack theory, FasL overexpression in RCC may be one of the host immune deficiencies, consequently leading to poor prognosis.

The bcl2 -938CC genotype has poor prognosis and lower survival in renal cancer

PURPOSE

A single nucleotide polymorphism (-938C/A, rs2279115) was found in the bcl2 gene, whose -938A allele is significantly associated with increased Bcl2 expression compared with that of the C allele. Bcl2 up-regulation was reported to be associated with longer survival in patients with renal cancer. However, to our knowledge there is currently no information on the role of the bcl2-938C/A single nucleotide polymorphism in renal cell carcinoma cases. Therefore, we investigated the polymorphism at the bcl2 -938C/A site and its effects on clinical characteristics in patients with renal cell carcinoma.

MATERIALS AND METHODS

We genotyped the bcl2-938C/A single nucleotide polymorphism in 216 patients with renal cancer, and in 209 healthy age and gender matched controls. We also investigated the relationship between the bcl2 -938C/A polymorphism, Bcl2 expression, proliferation and apoptosis status in renal cell carcinoma tissues using immunohistochemistry and TUNEL assay. The association of the bcl2 -938C/A single nucleotide polymorphism with survival in patients with renal cell carcinoma was also analyzed by Kaplan-Meier curves.

RESULTS

Survival in Bcl2 positive cases was significantly longer than in negative cases. On univariate and multivariate analyses the bcl2 -938CC genotype was independently associated with poor prognosis. Kaplan-Meier analysis showed that survival in patients with CC genotypes was significantly worse than in those with CA+AA genotypes. CC genotype carriers had significantly lower Bcl2 expression and higher proliferative activity in renal cancer tissues than CA+AA genotype carriers.

CONCLUSIONS

To our knowledge this is the first report to show that the bcl2 -938C/C genotype has worse prognosis and lower survival in patients with renal cell carcinoma. In addition, the bcl2 -938C/A single nucleotide polymorphism was shown to be an independent adverse prognostic factor for renal cell carcinoma.

Dynamics of cell proliferation and apoptosis reflect different life strategies in hydrothermal vent and cold seep vestimentiferan tubeworms

Deep-sea vestimentiferan tubeworms, which live in symbiosis with bacteria, exhibit different life strategies according to their habitat. At unstable and relatively short-lived hydrothermal vents, they grow extremely fast, whereas their close relatives at stable and long-persisting cold seeps grow slowly and live up to 300 years. Growth and age differences are thought to occur because of ecological and physiological adaptations. However, the underlying mechanisms of cell proliferation and death, which are closely linked to homeostasis, growth, and longevity, are unknown. Here, we show by immunohistochemical and ultrastructural cell cycle analyses that cell proliferation activities of the two species studied are higher than in any other characterized invertebrate, being only comparable with tumor and wound-healing processes. The slow growth in Lamellibrachia luymesi from cold seeps results from balanced activities of proliferation and apoptosis in the epidermis. In contrast, Riftia pachyptila from hydrothermal vents grows fast because apoptosis is down-regulated in this tissue. The symbiont-housing organ, the trophosome, exhibits a complex cell cycle and terminal differentiation pattern in both species, and growth is regulated by proliferation. These mechanisms have similarities to the up- and down-regulation of proliferation or apoptosis in various types of tumor, although they occur in healthy animals in this study, thus providing significant insights into the underlying mechanisms of growth and longevity.

Renal tumor natural history: the rationale and role for active surveillance

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. Despite widespread treatment at diagnosis, overall mortality rates associated with RCC have not decreased. Partly because of the more frequent use of abdominal imaging, diagnosis as an incidental finding has increased. The largest increase in incidence is in tumors smaller than 4 cm, termed small renal masses (SRMs). SRMs that are RCC may frequently be growth slowly and have a low risk of early progression. Initial active surveillance with delayed treatment for progression for selected patients should be considered. This should result in an overall decrease in treatment burden and cost saving.

Diagnostic and prognostic molecular markers in renal cell carcinoma

PURPOSE

We reviewed the contemporary literature on molecular biomarkers in renal cell carcinoma and their prognostic significance.

MATERIALS AND METHODS

Articles published during 1981 to 2007 in English on renal cell carcinoma were surveyed using the MEDLINE/PubMed database. The subject headings included were genetics, biomarkers, prognosis and risk models of renal cell carcinoma. We present a synthesis of currently known renal cell carcinoma biomarkers at various stages of development and their clinical significance, and prognostic nomograms incorporating biomarkers.

RESULTS

The beneficiary role of biomarkers in renal cell carcinoma is challenged by the relatively low prevalence of the disease. Even if a biomarker for renal cell carcinoma had 100% sensitivity and 99.4% specificity, the positive predictive value of the marker in men older than 65 years would be only 10%. Several biomarkers are being investigated in renal cell carcinoma, of which many relate to pathogenic molecular changes that are currently therapeutic targets. Carbonic anhydrase IX is a von Hippel-Lindau mediated enzyme that is expressed in most renal cell carcinoma cases. High (greater than 85%) expression of this marker indicates favorable prognosis and may predict the response to interleukin-2 therapy. B7-H1 expression in renal cell carcinoma cells/lymphocytes may indicate worse survival, possibly through impaired host antitumor immunity. Prognostic nomograms incorporating clinical variables and molecular markers to refine the prediction of treatment outcomes are in active development and await prospective clinical validation.

CONCLUSIONS

Several renal cell carcinoma molecular markers appear promising to refine the prognosis and prediction of localized, advanced or metastatic renal cell carcinoma. Currently carbonic anhydrase IX is the best studied and promising marker. Prospective, multicenter clinical validation aimed at the practical clinical usefulness of renal cell carcinoma biomarkers is warranted.

Molecular markers for predicting prognosis of renal cell carcinoma

Metastatic or recurrent renal cell carcinoma (RCC) carries a poor prognosis and long term survival is rare. However, many small RCCs that are incidentally discovered have an indolent course even without treatment. The variability in clinical outcome is a reflection of the underlying tumor biology. Currently, clinical variables such as tumor stage and histologic grade are widely accepted surrogates for tumor-specific cellular and molecular processes. Ongoing advances in genomic and proteomic technologies have produced an expanding list of molecular markers for predicting prognosis. We review expression array studies evaluating molecular signatures for predicting prognosis in patients with RCC and describe specific prognostic markers that have been validated in at least 50 cases of RCC.

The expression of p53-induced protein with death domain (Pidd) and apoptosis in oral squamous cell carcinoma

The Pidd (p53-induced protein with death domain) gene was shown to be induced by the tumour suppressor p53 and to mediate p53-dependent apoptosis in mouse and human cells, through interactions with components of both the mitochondrial and the death receptor signalling pathways. To study the role of Pidd in clinical tumours, we measured its expression by quantitative reverse transcription-PCR in microdissected oral squamous cell carcinomas (OSCC) with and without p53 mutation. Tumour cell apoptosis was assessed by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling. Tumour proliferation was assessed by immunohistochemical staining for the Ki-67 antigen. We found a wide range of Pidd expression among OSCC. Statistical analysis revealed an association between Pidd expression and apoptotic index (Mann-Whitney test, P<0.001), consistent with a role of Pidd in apoptosis in this tumour type. Furthermore, we showed a positive correlation between apoptotic index and proliferative index that has not been previously described for OSCC. There was no correlation between Pidd expression and the p53 mutation status of these tumours, suggesting that Pidd expression may be regulated by p53-independent mechanisms. Further characterisation of these molecular defects in the control of proliferation and apoptosis should help in developing treatments that target OSCC according to their biological properties.

Clinical symptoms in localized renal cell carcinoma reflect its invasive potential: comparative study between incidentally detected and symptomatic diseases

The objectives of this study were to analyze the association of clinical symptoms with several parameters in patients with organ-confined renal cell carcinoma (RCC), and investigate the difference in biologic characteristics between incidentally detected and symptomatic RCCs. This study included 132 patients who were pathologically diagnosed with organ-confined RCC after radical surgery, and their clinicopathologic features were compared to those in patients with incidentally detected and symptomatic diseases. In this series, 91 patients were incidentally diagnosed with RCC, while the remaining 41 had some clinical symptoms. The cause-specific survival in patients with incidental RCC was significantly higher than that in patients with symptomatic RCC, and the presence of clinical symptoms could be an independent predictor of cause-specific survival in these patients. Immunohistochemical staining of resected specimens from these patients were then performed with Ki-67, Bcl-2, matrix metalloproteinase (MMP)-2, MMP-9, and vascular endothelial growth factor antibodies. Despite the lack of differences in Ki-67, Bcl-2, and vascular endothelial growth factor expression between these 2 groups, significantly increased expressions of MMP-2 and MMP-9 in symptomatic RCCs were observed compared with those in incidental RCCs. Moreover, the presence of clinical symptoms in organ-confined RCC was significantly correlated with immunoreactivities of MMP-2 and MMP-9. These findings suggest that clinical symptoms have a significant impact on the prognosis of patients with organ-confined RCC and that the appearance of clinical symptoms may reflect the increased invasive potentials characterized by overexpression of MMPs.

Significance of Fas expression alteration during tumor progression of renal cell carcinoma

BACKGROUND

In order to characterize the alteration of apoptotic regulatory molecule expression during tumor progression of renal cell carcinoma (RCC), we compared the expression between tumor and normal tissues, and evaluated the relationship of the expression in tumors with pathological and clinical characteristics.

METHODS

Competitive reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) allowed the determination of Fas and bcl-2 mRNA and protein expression in surgically resected tumor and normal tissue of 50 RCC.

RESULTS

The mRNA expression of Fas and bcl-2 in RCC was significantly reduced compared to that in normal tissues. An IHC analysis was supportive of the RT-PCR results. In terms of relationships with pathological and clinical characteristics, the mRNA and protein expression of Fas in high-stage or high-grade tumors was significantly higher than that in low-stage or low-grade tumors. Moreover, a statistically poor prognosis was observed in tumor cases expressing a high amount of mRNA. In bcl-2 analysis, the mRNA and protein expression was significantly reduced in clear cell tumors compared to chromophobe cell tumors.

CONCLUSION

It is suggested that the reduced expression of Fas and bcl-2 in RCC compared with the expression in normal kidney is a prominent alteration of apoptotic regulatory molecules. The alteration of the up-regulated Fas expression might be characterized during the tumor progression stage. It is also suggested that the effect of alteration of bcl-2 expression might be minimal during the tumor progression stage because of the reduced expression in tumors of the clear cell type, which is the most dominant cell type in RCC.

Biochemical and molecular markers in renal cell carcinoma: an update and future prospects

Cancer is a big problem in the developed world as well as in developing countries. Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 90-95% of neoplasms arising from the kidney. RCC is more common in men than in women (2:1), and it most often occurs in patients between the ages of 50-70 years. In all cancers the cancerous cells release particular kind of proteins (called tumour markers) and blood tests are used to detect the presence of these markers. These tumour markers nowadays are an area of interest for oncologists who search for a possible solution in the detection and treatment of RCC. Different kinds of biochemical and molecular markers such as ferritin, MN/CA9, apoptotic index, p53, IL-2, gamma-enolase, CD44, CD95, chromosome instability and loss of heterozygosity have been tested in RCC, but so far no marker fulfils one or the other criteria to be considered as an ideal marker for RCC. This review gives basic and updated information about the different kinds of biomarkers studied in RCC and about the role implementation of genomics and proteomics in RCC.

Natural history of small renal cell carcinoma: evaluation of growth rate, histological grade, cell proliferation and apoptosis

PURPOSE

We investigated the natural history of incidentally discovered small renal cell carcinomas (RCCs), and we evaluated growth rate, apoptosis, cell proliferation and histological grade.

MATERIALS AND METHODS

A total of 18 patients with RCCs extirpated after at least 12 months of observation were reviewed retrospectively. The period of observation ranged from 12 to 63 months (median 22.5). Median patient age was 56.5 years, ranging from 37 to 71. Annual tumor growth rate was calculated from diameter obtained from computerized tomography or ultrasound. Cell proliferation and apoptosis were assessed by immunostaining using Ki-67 and TUNEL.

RESULTS

Average tumor growth rate was 0.42 cm per year (standard error 0.09, 95% confidence interval 0.24 to 0.61). Of the 18 tumors 7 were grade 1, 8 were grade 2 and 3 were grade 3. Tumor growth rate and Ki-67 positive ratio were not correlated. In contrast, growth rate and positive ratio of TUNEL were significantly correlated. A significant difference in growth rate was observed between grade 2 and 3 tumors but not between grade 1 and 2 tumors.

CONCLUSIONS

The growth rate of RCCs correlates with apoptosis and grade. Most incidentally found RCCs are slow growing. However, those with certain histopathological features can grow rapidly and have a poor prognosis. More attention should be given to the observation of small renal masses.

Downregulation of Bcl-2 sensitises interferon-resistant renal cancer cells to Fas

Interferon α (IFNα) is used to treat patients with advanced renal cell carcinoma (RCC) despite limited clinical benefit. IFNα can induce Fas receptor-mediated apoptosis by direct activation of pro-caspase-8 followed by activation of caspase-3. Alternative, indirect activation of caspase-3 via mitochondrial release of cytochrome c can occur and may explain the rescue from Fas-activated cell death by the antiapoptotic members of the Bcl-2 family. In this study, we examined G3139, a novel antisense compound targeting Bcl-2, in combination with IFNα. Human RCC lines (SK-RC-44 and SK-RC-07) were treated with IFNα, G3139 or a combination of the two. Fas-mediated cytotoxicity was induced by anti-Fas mAb, CH11. An analysis of Bcl-2, Fas and the cleavage of PARP was performed. IFNα induced Fas and Bcl-2 in SK-RC-44 and SK-RC-07. IFNα sensitised SK-RC-44 to anti-Fas and induced PARP cleavage confirming that IFNα has a cytotoxic effect on RCC lines by induction of the Fas antigen. Cytotoxicity was not evident in SK-RC-07 cells treated with IFNα. G3139 induced a specific downregulation of Bcl-2 in SK-RC-07 cells, which were then sensitised to anti-Fas after treatment with IFNα. Taken together, these results suggest that Fas-dependent pathways as well as alternative pathways, which can be inhibited by Bcl-2, exist in renal cell carcinoma. G3139 in combination with IFNα is a potential therapy in patients with metastatic renal cell carcinoma.

Prognostic value of the expression of Ki-67, CD44 and vascular endothelial growth factor, and microvessel invasion, in renal cell carcinoma

OBJECTIVE

To determine if use of cell proliferation, cell adhesion, level of angiogenesis-related factors and presence of microscopic vascular invasion (MVI) could better predict the biological behaviour of renal cell carcinoma (RCC), which has a widely variable clinical outcome despite the use of conventional prognostic factors (staging and grading).

MATERIALS AND METHODS

The expression of Ki-67, CD44H and vascular endothelial growth factor (VEGF) were assessed immunohistochemically in formalin-fixed, paraffin-embedded tissues from 48 RCCs, using a Ki-67 labelling index (LI), CD44 LI and level of VEGF expression, respectively. In addition all the pathological slides were reviewed retrospectively for the presence and absence of MVI. The prognostic value of all the variables assessed was then evaluated, and correlated with the usual prognostic variables and cancer-specific survival.

RESULTS

Univariate analysis of cancer-specific survival showed that tumour stage (P < 0.001), tumour size (P = 0.005), metastasis, MVI, Ki-67 LI, CD44H LI and VEGF expression (all P < 0.001) were predictors of tumour-related death. There was a statistical correlation between CD44H LI and each of Ki-67 LI (r = 0.61), expression level of VEGF (r = 0.72) and presence of MVI (r = 0.71). Independent predictors of cancer-specific survival in a multivariate analysis were: in all patients with RCC, the MVI (P = 0.003) and VEGF expression (P = 0.01); in those with no metastases, MVI (P = 0.01); in patients with no MVI, VEGF (P = 0.04); and in patients with MVI, Ki-67 LI (P = 0.003). No independent predictor was identified in patient with metastases.

CONCLUSION

This study suggests that cell proliferation, cell adhesion, the level of VEGF expression and the presence of MVI represent a complex tumour-host interaction that may favour the progression of RCC. Cell proliferation, CD44H and VEGF expression appear to be powerful markers for identifying patients with an adverse prognosis.

Impact of frequent Bcl-2 expression on better prognosis in renal cell carcinoma patients

Previously, we reported that Bcl-2 was frequently expressed in renal cell carcinoma (RCC) specimens, but p53 mutation was a rare event. However, it was unclear whether Bcl-2 positivity was associated with the clinicopathological characteristics and prognosis in RCC. Therefore, we investigated the expression of Bcl-2 protein and its roles in 101 RCC specimens. In addition, the proliferation index (PI), apoptotic index (AI), caspase-3 and p53 expression were examined. The immunohistochemical method was applied for Bcl-2, caspase-3 and p53 protein expression. To investigate the proliferation activity and apoptosis of tumour cells, PI and AI were calculated based on Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL)-positive cells, respectively. Bcl-2 expression was detected in 72 out of 101 (71.3%) specimens. Bcl-2 positivity was inversely correlated with PI (P<0.0001) and AI (P=0.0074). Furthermore, Bcl-2 positivity was significantly correlated with better survival (P=0.0014), and was associated with lower stage (P=0.0301) and grade (P=0.0020). In RCC, frequent Bcl-2 expression was correlated with favourable character without higher PI and AI. Thus, Bcl-2 expression might be applied as a novel predictor of better prognosis in RCC patients.

The relationship of expression of bcl-2, p53, and proliferating cell nuclear antigen (PCNA) to cell proliferation and apoptosis in renal cell carcinoma

To investigate the relationship of bcl-2, p53, proliferating cell nuclear antigen (PCNA) to cell proliferation, apoptosis and pathological parameters, the patterns of cell growth and turnover in renal cell carcinoma (RCC), formalin-fixed and paraffin-embedded tissue blocks from 34 patients with RCC were examined. Cell proliferation activity was detected by PCNA immunostaining and the proliferation index (PI) was expressed as a percentage of the PCNA-positive cells in the tumor cells. Apoptosis was detected by terminal deoxy- nucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and the apoptotic index (AI) was expressed as a percentage of the TUNEL-positive cells in the tumor cells. Expressions of bcl-2 and p53 were assessed immunohistochemically. Our results showed that the PI ranged from 6.0% to 24.0% (median 12.3%) and the AI from 2.0% to 8.0% (median 5.4%) in RCC. The expression of the bcl-2 protein was demonstrated in 15 cases (44.1%); the expression of the p53 protein, however, was seen in only 3 case. bcl-2 positivity was not associated with PI or AI or any pathological parameters. There were close associations between PI and tumor grade and stage, and a significant relationship between AI and the tumor grade of RCC, Our study suggests that bcl-2 positivity was not associated with PI or AI or any pathological parameters. There are close associations between PI and AI and tumor grade and stage of RCC. Active cell proliferation may be accompanied by frequent apoptosis in RCC.

Cell proliferation, apoptosis, angiogenesis and growth rate of incidentally found renal cell carcinoma

BACKGROUND

Our previous study showed that the growth rate of incidentally found renal cell carcinoma (RCC) varied, and that the initial clinical and pathological features did not predict subsequent growth of the carcinoma. The objective of this study was to determine the relationships between cell proliferation, apoptosis, angiogenesis and the growth rates of these RCC.

METHODS

We examined cell proliferation, apoptosis, and angiogenesis in 16 incidentally found cases of RCC. Cell proliferation was assessed by immunohistochemical staining with a Ki-67 antibody. Apoptosis was assessed by the terminal deoxynucleotidyl transferase (TdT) mediated deoxy-UTP biotin nick end labeling (TUNEL) technique. The Ki-67 labeling index (KI) and the apoptotic index (AI) were determined as the ratio of immunohistochemically positive cells per 1000 cancer cells. The KI/AI ratio was also determined. Angiogenesis was evaluated by CD34 immunostaining. Finally, we investigated the correlation between these parameters and the growth rate of primary lesions of incidentally found RCC.

RESULTS

The KI ranged from 7 to 73 (median, 20), AI ranged from 6 to 171 (median, 26), and microvessel density (MVD) ranged from 21 to 673 (median, 265) for incidentally found RCC. Ki-67 labeling index, AI and MVD were not closely correlated to each other. Furthermore, these parameters were not associated with growth rates of incidentally found RCC. Only the KI/AI ratio was strongly correlated to the growth rate of incidentally found RCC (r = 0.709; P = 0.0083).

CONCLUSION

Our results suggest that the balance between cell proliferation and apoptosis partly determines the growth rate of primary lesions of incidentally found RCC.

The role of rational immunotherapy for renal cell carcinoma

Metastases to distant organs are the principal cause of death from renal cell carcinoma (RCC). No commonly accepted therapy is available for disseminated RCC at present. The rationale for immunotherapy of RCC is based on the fact that there is no other therapy for advanced cases. Biologic therapies are the only current treatment modalities that have produced promising therapeutic results in metastatic RCC (mRCC). Therapy with cytokines usually has typical and sometimes severe side effects. Response rates and toxicity were higher with combined therapy. The administration of cytokines that augment the function of the immune system can be accomplished safely and without toxicity, provided a rational approach is used. The toxic effects that are frequently observed with combined therapy emphasize the need for careful selection of patients.

[Apoptosis in renal adenocarcinoma. Expression of bcl-2 in locally confined tumors]

INTRODUCTION AND OBJECTIVE

Bcl-2 is a proto-oncogene known to be a negative regulator of apoptosis, whose expression conferring prolonged cell survival and contributing to tumorigenesis. Inconsistent results concerning bcl-2 expression and the frequency of apoptosis were noted in renal cell carcinoma. To investigate a possible role of bcl-2 protein in renal cell carcinomas, we analyzed its expression and relationship with clinical and pathological parameters, including prognostic impact.

METHODS

58 patients diagnosed of renal cell carcinoma stage pT1, pT2 and pT3a N0 M0 (TNM 1997) were treated by radical or partial nephrectomy. We analyzed clinical and pathological parameters including bcl-2 expression in paraffin-embedded tumor samples using immunohistochemical technique.

RESULTS

Bcl-2 immunopositivity was detected in 44/58 of the samples in different grades of intensity. There was no correlation of nuclear grade, tumoral size, stage or recurrency with bcl-2 immunopositivity. Bcl-2 expression was not related to prognosis if we divided all cases into subgroups according of stain intensity.

CONCLUSIONS

Bcl-2 expression was not related with any pathological parameters; size, nuclear grade and stage or prognostic.