Expression of bcl-2 protein in stage T1N0M0 non-small cell lung carcinoma

Prognostic value of Bcl-2 expression in patients with non-small-cell lung cancer: a meta-analysis and systemic review

Objective

B-cell-lymphoma-2 (Bcl-2) is a proto-oncogene that plays an important role in the regulation of apoptosis and cell survival. However, there are much conflicting data in the literature concerning the association between Bcl-2 and prognosis in non-small-cell lung cancer (NSCLC). There is little in the way of meta-analysis focused on Bcl-2 and its effect on NSCLC prognosis. This study was performed to provide an assessment of whether expression levels of Bcl-2 are associated with prognosis in patients with NSCLC.

Materials and methods

We searched PubMed, the Cochrane Library, and China National Knowledge Infrastructure for all eligible studies. The combined hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) in terms of overall survival were evaluated.

Results

Fifty published studies including 6,863 patients with lung cancer were included in this meta-analysis. Overall, Bcl-2 was expressed in 33% of the NSCLC tumors studied. Our analysis indicates that NSCLC patients with Bcl-2-positive expression have a better prognosis than those with Bcl-2-negative expression in both Asian and non-Asian study populations (HR 0.79, 95% CI 0.72–0.87, P<0.00001). However, Bcl-2-positive expression seems to have no significant impact on survival of stage I NSCLC patients.

Conclusion

Our results indicated that Bcl-2 might be a useful prognostic marker for NSCLC generally. Larger clinical trials are needed to confirm the prognostic value of Bcl-2 in stage I NSCLC.

High expression of Bcl-2 protein predicts favorable outcome in non-small cell lung cancer: evidence from a systematic review and meta-analysis

BACKGROUND

The prognostic value of Bcl-2 protein expression in non-small cell lung cancer (NSCLC) is under debate. We therefore systematically reviewed the evidence for Bcl-2 protein effects on NSCLC survival to elucidate this issue.

MATERIALS AND METHODS

An electronic search in Pubmed and Embase complemented by manual searches in article references were conducted to identify eligible studies to evaluate the association between Bcl-2 protein expression and overall survival (OS) as well as disease free survival (DFS) of NSCLC patients. Combined hazard ratios (HRs) with corresponding 95% confidence intervals (95%CIs) were pooled using the random-effects model.

RESULTS

A total of 50 trials (including 52 cohorts) encompassing 7,765 patients were pooled in the meta-analysis regarding Bcl-2 expression and OS of NSCLC patients. High expression of Bcl-2 protein had a favorable impact (HR=0.76, 95%CI=0.67-0.86). In the group of Bcl-2 expression and DFS, 11 studies including 2,634 patients were included. The synthesized result indicated high expression of Bcl-2 protein might predict good DFS (HR=0.85, 95%CI=0.75-0.95).

CONCLUSIONS

Our present meta-analysis demonstrated favorable prognostic values of Bcl-2 expression in patients with NSCLC. Further prospective trails are welcomed to validate the utility of assessing Bcl-2 in NSCLC patient management.

High expression of BCL-2 predicts favorable outcome in non-small cell lung cancer patients with non squamous histology

Background

Bcl-2 promotes cell survival by inhibiting adapters needed for the activation and cleavage of caspases thus blocking the proteolytic cascade that ultimately dismantles the cell. Bcl-2 has been investigated as a prognostic factor in non small cell lung cancer (NSCLC) patients with conflicting results.

Methods

Here, we quantitatively assessed Bcl-2 expression in two large and independent cohorts to investigate the impact of Bcl-2 on survival. AQUA^®, a fluorescent-based method for analysis of in situ protein expression, was used to measure Bcl-2 protein levels and classify tumors by Bcl-2 expression in a cohort of 180 NSCLC patients. An independent cohort of 354 NSCLC patients was used to validate Bcl-2 classification and evaluate outcome.

Results

Fifty % and 52% of the cases were classified as high expressers in training and validation cohorts respectively. Squamous cell carcinomas were more likely to be high expressers compared to adenocarcinomas (63% vs. 45%, p = 0.002); Bcl-2 was not associated with other clinical or pathological characteristics. Survival analysis showed that patients with high BCL-2 expression had a longer median survival compared to low expressers (22 vs. 17.5 months, log rank p = 0.014) especially in the subset of non-squamous tumors (25 vs. 13.8 months, log rank p = 0.04). Multivariate analysis revealed an independent lower risk for all patients with Bcl-2 expressing tumors (HR = 0.53, 95% CI 0.37-0.75, p = 0.0003) and for patients with non-squamous tumors (HR = 0.5, 95% CI 0.31-0.81, p = 0.005).

Conclusions

Bcl-2 expression defines a subgroup of patients with a favorable outcome and may be useful for prognostic stratification of NSCLC patients.

A small molecule pan-Bcl-2 family inhibitor, GX15-070, induces apoptosis and enhances cisplatin-induced apoptosis in non-small cell lung cancer cells

PURPOSE

Overexpression of Bcl-2 family members as well as deregulated apoptosis pathways are known hallmarks of lung cancer. Non-small cell lung cancer (NSCLC) cells are typically resistant to cytotoxic chemotherapy and approaches that alter the balance between pro-survival and pro-death Bcl-2 family members have shown promise in preclinical models of NSCLC.

METHODS

Here we evaluated the effects of a novel pan-Bcl-2 inhibitor GX15-070 on NSCLC survival and when combined with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors as well as traditional cytotoxic agents. GX15-070 is a small molecule agent that binds anti-apoptotic Bcl-2 proteins and interferes with their ability to interact with pro-apoptotic proteins. We evaluated the effect of GX15-070 and correlated the effect on EGFR status as well as Bcl-2 family protein expression.

RESULTS

We show that GX15-070 can disrupt Mcl-1:Bak interactions in lung cancer cells. We identified differential sensitivity of a panel of lung cancer cells to GX15-070 and no clear relationship existed between EGFR status or Bcl-2 family protein expression and sensitivity to GX15-070. GX15-070 could induce apoptosis in a subset of lung cancer cell lines and this correlated with the effects on cell viability. GX15-070 combined with gefitinib was synergistic in a cell line dependent on EGFR for survival but GX15-070 could not reverse resistance to gefitinib in cell lines not dependent on EGFR for survival. Finally, we observed synergy between GX15-070 and cisplatin in NSCLC cells.

CONCLUSIONS

Based on these results, GX15-070 can trigger apoptosis in NSCLC cells and can enhance chemotherapy-induced death. These data suggest that clinical trials with GX15-070 in combination with cytotoxic chemotherapy are indicated.

Immunohistochemical analysis of non-small cell lung cancer: correlation with clinical parameters and prognosis

Non-small cell lung cancers (NSCLC) vary in their biologic behavior. Recurrence and tumor-related mortality may be attributable to molecular abnormalities in primary tumors. This study evaluated such immunophenotypes with regard to cell cycle regulation and proliferation, apoptosis, and angiogenesis, to determine their significance for patient outcome. Core biopsies from 219 patients with NSCLC were assembled on tissue microarrays, and the expressions of p16, p21, p27, cyclin B1, cyclin E, Ki-67, caspase-3, survivin, bcl-2, VEGF, and endostatin were evaluated by immunohistochemistry. Despite previously described prognostic relevance of some of the investigated molecules, many of those markers were not directly associated with recurrence or survival. However, there was a trend for p16 immunoreactivity to be associated with a good prognosis (57% vs. 42% in 5-yr survival) (p=0.071). bcl-2 expression was strongly correlated with a better outcome (65% vs. 45% in 5-yr survival) (p=0.029), and the hazard of death for bcl-2 positive patients was 0.42 times of that for bcl-2 negative patients (p=0.047). A multivariate analysis with Cox proportional hazards model confirmed that the lymph node status (p=0.043) and stage (p=0.003) were other independent prognostic factors. Our results suggest that p16 and bcl-2 provide prognostic information independent of the TNM stage in NSCLC.

Antiapoptotic signaling pathways in non-small-cell lung cancer: biology and therapeutic strategies

One of the hallmarks of lung cancer is the deregulation of apoptotic or programmed cell death mechanisms usually found in normal cells that allow for corrupted cells to undergo cellular suicide. This includes mechanisms that attenuate proapoptotic pathways and/or amplify antiapoptotic pathways. Increasing evidence suggests that lung cancer cells use multiple and perhaps redundant pathways to maintain survival. Increasing knowledge of these pathways offers a better understanding of the biology of lung cancer as well as novel therapeutic strategies that can enhance lung cancer cell death. This review discusses the apoptotic machinery and signal transduction pathways that regulate apoptosis, methods of identifying the presence of activated survival signaling pathways in human lung cancers, and the clinical significance and relevance for therapy for patients with lung cancer.

Endometrial Hyperplasia: A Review

Endometrial hyperplasia is a precursor to the most common gynecologic cancer diagnosed in women: endometrial cancer of endometrioid histology. It is most often diagnosed in postmenopausal women, but women at any age with unopposed estrogen from any source are at an increased risk for developing endometrial hyperplasia. Hyperplasia with cytologic atypia represents the greatest risk for progression to endometrial carcinoma and the presence of concomitant carcinoma in women with endometrial hyperplasia. Abnormal uterine bleeding is the most common presenting symptom of endometrial hyperplasia. Specific Pap smear findings and endometrial thickness per ultrasound could also suggest the diagnosis. Unopposed estrogen in women taking hormone replacement therapy increases the risk of endometrial hyperplasia. Tamoxifen has demonstrated its efficacy in treating women at risk for breast cancer, but it increases the risk of endometrial hyperplasia. The choice of treatment for endometrial hyperplasia is dependent on patient age, the presence of cytologic atypia, the desire for future childbearing, and surgical risk. Endometrial hyperplasia without atypia responds well to progestins. However, women with atypical hyperplasia should be treated with hysterectomy unless other factors preclude surgery.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the definition and classification of endometrial hyperplasia, to outline the clinical features of a patient with endometrial hyperplasia, to point out the natural history of endometrial hyperplasia, and to summarize the diagnostic options for patients with endometrial hyperplasia.

Expression of bcl-2 protein is associated with shorter survival in nonsmall cell lung carcinoma

BACKGROUND

The aim of this study was to assess the relationship between the expression of the 27-kilodalton (kD) bcl-2 protein and survival among nonsmall cell lung carcinoma (NSCLC) patients.

METHODS

Paired tissue samples of histologically confirmed tumor and uninvolved lung of 91 randomly selected NSCLC patients were used in this study. The expression of 27-kD bcl-2 proteins in uninvolved lung and tumor tissue specimens was analyzed using Western blot analysis. Overall survival was estimated using the Kaplan-Meier method. The relation between patient survival and expression of the 27-kD bcl-2 protein in uninvolved lung, tumor, and in uninvolved lung and/or tumor tissue specimens was assessed using log-rank tests and Cox proportional hazards multiple regression.

RESULTS

The 27-kD bcl-2 protein was expressed in 54% of the uninvolved lung tissue specimens, in 53% of the tumor tissue specimens, and in 70% of the uninvolved lung and/or tumor tissue specimens. When NSCLC patient survival was considered with respect to the expression of the 27-kD bcl-2 protein, a statistically significant shorter survival was observed for patients whose tissue samples expressed the 27-kD bcl-2 protein in the uninvolved lung and in the uninvolved lung and/or tumor (log-rank test, P = 0.008 and P = 0.001, respectively). Cox proportional hazards multiple regression models also showed statistically significant associations between shorter survival and positive 27-kD protein expression in the uninvolved lung (hazard ratio of 2.27; P = 0.05) and in the uninvolved lung and/or tumor (hazard ratio of 5.58, P = 0.008) after controlling for tumor size, stage, the type of surgery received, smoking status, age, and cell type.

CONCLUSIONS

In the current study, patients with nonsmall cell lung carcinoma with positive expression of the 27-kD protein bcl-2, either in the uninvolved lung or in uninvolved lung and/or tumor, were found to have significantly poorer postresection survival.

Prognostic significance of K-ras, p53, bcl-2, PCNA, CD34 in radically resected non-small cell lung cancers

The aim of this study was to investigate the prognostic significance of a panel of biological parameters in patients with radically resected non-small cell lung cancers (NSCLC). 269 cases with pathological stage I-IIIA NSCLC were retrospectively analysed. Immunohistochemistry was performed to detect protein expression of p53, bcl-2, proliferating cell nuclear antigen (PCNA) and CD34. Polymerase chain reaction (PCR)/direct nucleotide sequencing method was used to detect mutations in K-ras (codons 12, 13, 61, exons 1-2). The Kaplan-Meier estimates of survival were calculated for clinical and biological variables using the Cox model for multivariate analysis. Histological subtype and the pathologic tumour extension (pT) were the most powerful clinical-pathological prognostic factors for survival (P=0.030 and P=0.031, respectively), whereas among the biological parameters, p53 overexpression (P=0.032) and K-ras mutation (P=0.078) had a negative prognostic role, as demonstrated by multivariate analysis. Conversely, bcl-2, PCNA and CD34 expression were not correlated with survival. Statistically significant associations between p53 expression and the squamous cell carcinoma (SCC) subtype, bcl-2 expression and SCC subtype, K-ras mutation and p53 negative expression, p53 and bcl-2, bcl-2 and PCNA overexpression were observed. In conclusion, some biological characteristics such as the K-ras and p53 status may provide useful prognostic information in resected NSCLC patients, in addition to the classical clinico-pathological parameters. However, further studies are needed to clarify the value of adopting biological prognostic factor into clinical practice.

Clinical relevance of molecular markers in lung cancer

The last two decades have seen an exponential growth of our knowledge on the molecular biology of cellular processes and neoplastic transformation. There is high expectation that these advances will be translated into further improvement in the care of cancer patients, especially in the areas of prevention, diagnosis and treatment. Realizing that the histopathological classification of lung cancer has reached its limit in providing additional critical information to further improve treatment strategy, numerous molecular aberrations occurring in lung cancers have been explored as potential new diagnostic markers and markers for molecular sub-staging. Despite extensive studies, most results remain largely controversial. This manuscript will briefly review molecular/genetic changes that have been investigated as candidate diagnostic, prognostic and predictive markers and as biomarkers for early detection in lung cancer. A more concerted and global approach to study the clinical relevance of molecular changes in lung cancers is required in the future.

The Role of Apoptosis-Related Genes in non—small-Cell Lung Cancer

Both intrinsic and acquired resistance to chemotherapeutic drugs are major obstacles in the treatment of non-small-cell lung cancer. Apart from classical drug resistance mechanisms, the failure of tumor cells to undergo apoptosis also plays an important role in drug resistance. Mutations and defects in the apoptotic pathway are, therefore, additional factors that determine drug resistance. The tumor suppressor gene p53, the retinoblastoma gene, and the bcl-2 family members are important factors in this pathway. Recently much attention has been drawn to different apoptotic pathways induced by naturally occurring death receptor ligands (such as tumor necrosis factor, Fas ligand, and tumor necrosis factor-related apoptosis-inducing ligand) or induced by drugs that affect the downstream pathway from the epidermal growth factor receptor. Insight regarding the proteins that determine sensitivity for chemotherapeutic drugs could provide new targets for cancer treatment, which may help to at least partly overcome drug resistance in non-small-cell lung cancer

Blood vessel invasion in resected non small cell lung carcinomas is predictive of metastatic occurrence

Prognosis of patients with non small cell lung cancer (NSCLC) remains difficult to assess, even after adjustment for pathological stage. Prognostic value of numerous biological markers has been evaluated, with conflicting results. Data of 86 patients with NSCLC treated by surgery were collected with clinical characteristics, histopathological data including tumor differentiation and status of blood and lymphatic vessel invasion and evaluation by immunohistochemistry of Rb, Bcl-2 and Ki-67 expression. Prognostic values for overall survival (OS) and event-free survival (EFS) were analyzed by the log tank test and the multivariable Cox model. Using univariable analyses, pT, pN, poor differentiation or large cell subtype were associated with a poor OS, while lymphatic and/or blood vessel invasion were associated with a short EFS. None of the molecular markers had a significant prognostic value for either outcome. In multivariable analyses, only stage remained of prognostic value for OS. Interestingly, the presence of blood vascular invasion in the tumor was significantly predictive for subsequent metastatic occurrence in stages I and II. This feature might, therefore, be relevant for administration of adjuvant therapy in completely resected NSCLC.

Prognostic significance of p53 and bcl-2 abnormalities in operable nonsmall cell lung cancer

The association of p53 abnormalities and bcl-2 protein expression with clinical data and prognosis in 102 patients with resected nonsmall cell lung cancer (NSCLC) was investigated. Deoxyribonucleic acid analysis of exons 5-8 of the p53 gene showed mutations (p53-M) in 47% of resected NSCLC, serum p53 antibodies (p53-Abs) were detected in 25%, p53 protein overexpression (p53-PE) in 54%, and bcl-2 protein overexpression (bcl-2-PE) in 48%. A statistically significant association was found between p53-PE, serum p53-Abs and the presence of a p53 gene alteration. No significant associations were found between results of the p53-M, p53-Abs, bcl-2-PE tests and clinicopathological parameters. In the case of the p53-PE test there were significantly fewer positive results for adenocarcinoma than for squamous cell carcinoma and large cell carcinoma. Survival analysis showed that both p53 abnormalities and negative staining for bcl-2, when analysed separately, were associated with poor overall survival. In a multivariate analysis, only the positive result of the p53-M test remained an independent, statistically significant, unfavourable prognostic factor for survival. When the p53 mutation test was removed from the model, positive results of the p53-PE test and the p53-Abs test became statistically significant, unfavourable prognostic factors. To conclude, among p53 and bcl-2 abnormalities, only p53 gene mutations seem to have a strong and independent effect on prognosis. When deoxyribonucleic acid sequence information is not available, p53 protein expression and the presence of p53 antibodies in serum may be used to obtain important prognostic information.

Survival in small cell lung carcinoma is independent of Bcl-2 expression

Bcl-2 overexpression is a common event in small cell carcinomas (SCLC). The bcl-2 oncoprotein has a unique oncogenic role by inhibiting programmed cell death (apoptosis), resulting in tumorigenesis and chemoresistance. Forty-two cases of SCLC were stained immunohistochemically with bcl-2 monoclonal antibody (Biogenex, San Ramon, CA) after using an antigen retrieval step with citrate buffer. bcl-2 positivity was determined as detection of the oncoprotein in greater than 10% of noncrushed neoplastic cells. Twenty-five of 42 (60%) patients had extensive disease at presentation, 10 of 42 (24%) had limited disease, and 7 of 42 (16%) had disease localized to the lung. Twenty-four of 42 (57%) tumors were bcl-2 positive, and 18 of 42 (43%) tumors were bcl-2 negative. Follow-up in patients ranged from 7 days to 96 months (mean follow-up, 20 months). The median survival of patients with bcl-2-positive tumors was 11 months, as opposed to 13 months for bcl-2-negative tumors. There was no significant difference in median survival between bcl-2-positive and bcl-2-negative SCLC (log rank test, P = .2256). Using Cox's proportional hazards model, median survival in SCLC was determined to be independent of age at diagnosis, stage at presentation, therapeutic modality, and bcl-2 expression. bcl-2 expression does not significantly influence survival in SCLC.

trans E1 component requirements for maximal replication of E1-defective recombinant adenovirus

Strategies that enable E1-defective recombinant adenoviruses to selectively undergo replication in neoplastic tissue may be useful for future investigations or therapies of malignancies. A growing body of evidence suggests that some molecular alterations commonly associated with malignancies, such as p53 mutations, can modify the specific E1 requirements for replication of human serotype adenoviruses. In the studies reported here, a panel of human non-small cell lung cancer cell lines with previously defined p53 status were characterized for basal interleukin-6 (IL-6) and bcl-2 content because previous studies have indicated both proteins can functionally substitute for the replication requirements provided by native E1 viral proteins. Cell lines were infected with E1-defective adenovirus 5 and simultaneously transfected with different combinations of E1 plasmids, or a bcl-2 expression plasmid, and adenovirus present in the cells was quantified 6 days later. These assays demonstrated that E1A with both 19- and 55-kDa E1B-encoding plasmids were required for maximal adenoviral replication, independent of the varying p53/IL-6/basal bcl-2 phenotypes of the host cell lines. E1A was required for maximal replication enablement, independent of the basal IL-6 content of these cell lines, and exogenous IL-6 also did not obviate the E1A requirement. Interestingly, the bcl-2 expression plasmid did not consistently substitute for the 19-kDa expression plasmid in the context of this replication complementation assay. These results suggest that (1) basal levels of IL-6 greater than that present in these cell lines are necessary for functional replacement of the E1A replication function and (2) bcl-2 does not predictably substitute for the 19-kDa E1B replication function in the context of trans complementation.

Epstein-Barr virus-associated nonsmall cell lung carcinoma: undifferentiated "lymphoepithelioma-like" carcinoma as a distinct entity with better prognosis

BACKGROUND

Epstein-Barr virus (EBV) infection in nonsmall cell lung carcinoma (NSCLC) has been demonstrated in some ethnic groups. The pathobiology and the role of EBV and oncoprotein expression in these tumors have not been studied extensively. In this study, the authors investigated EBV-encoded RNA-1 (EBER1) transcripts by in situ hybridization and the expression of latent membrane protein-1 (LMP-1) and bcl-2 protein by immunohistochemistry in NSCLC patients from Taiwan, where nasopharyngeal carcinoma is endemic.

METHODS

A total of 127 cases of NSCLC (43 cases of squamous cell carcinoma [SCC], 67 cases of adenocarcinoma [AD], 12 cases of large cell carcinoma [LCC], and 5 cases of lymphoepithelioma-like carcinoma [LE]) were included. A sensitive polymerase chain reaction-derived, digoxigenin-labeled DNA probe for in situ detection of EBER1 transcripts was performed for the detection of EBV. Immunohistochemistry using the avidin-biotin-immunoperoxidase method was also performed to evaluate the expression of bcl-2 and LMP-1.

RESULTS

EBER1 was detected in 11 of the 127 NSCLC cases (8.7%; 6 SCC cases and 5 LE cases). All 5 LE cases were EBV-positive, whereas only 6 of the 43 SCC cases (14%), 0 of 67 AD cases, and 12 LCC cases were EBV-positive (P < 0.05). All five LE cases showed diffuse, strong, positive staining of tumor cells; five of the six SCC cases showed diffuse but weak staining. Among the nontumor epithelial cells, there was no EBER1 staining of any of the 11 EBER1-positive cases. The mean age of the LE patients was 10 years younger than that of the patients with other histological types. All 5 LE patients were nonsmokers, whereas 3 of the 6 patients with EBER1-positive SCC (50%) were smokers. EBER1 expression did not correlate with the 2-year survival rate of overall cases, but all 5 LE patients were alive without clinical evidence of disease at last follow-up. Gender, lymph node or distant metastasis, and clinical stage were not found to have any correlation with EBER1 expression (P > 0.05). All LE cases had bcl-2 oncoprotein expression (100%). This frequency was significantly different from other histologic types (P < 0.05). The LMP-1 detection rate was low and demonstrated no correlation with bcl-2 expression.

CONCLUSIONS

In this study, the authors found that the primary LE of the lung is associated with young age, a history of not smoking, high bcl-2 immunoreactivity, and better survival rate. These characteristics demonstrate that EBV-associated LE of the lung is a unique entity. The findings of the current study suggest that EBV infection may play a different role in the tumorigenesis of primary LE of the lung than it does in other EBER1-positive NSCLCs.

Immunohistochemical evaluation of bcl-2 oncoprotein in oral dysplasia and carcinoma

The proto-oncogene bcl-2 is associated with follicular lymphoma involving translocation t(14;18)(q32;q21) and is also overexpressed in various neoplasms. We report deregulation of bcl-2 expression during progression from oral epithelial dysplasia to squamous cell carcinoma. Immunohistochemical analysis with monoclonal antibodies to bcl-2 oncoprotein in formalin-fixed paraffin-embedded tissue sections revealed that severe epithelial dysplasias had a higher percentage of immunoreactivity than did mild and moderate dysplasias and squamous cell carcinomas. Expression of this oncoprotein was directly proportional to the degree of epithelial dysplasia, and nondysplastic basal cells contiguous to neoplastic lesions also expressed bcl-2. These findings, along with down-regulation of bcl-2 in differentiating carcinomas, suggest a role for this oncoprotein in relatively early stages of oral tumor progression. Differentiating neoplastic cells with marginal or no bcl-2 reactivity showed heterogeneous cell labeling of varying intensity for differentiation-associated cytokeratin (CK13), indicating their inverse topographic relationship.

Absence of prognostic significance of bcl-2 immunopositivity in non-small cell lung cancer: analysis of 427 cases

The bcl-2 gene product inhibits apoptosis and is thought to participate in oncogenesis. Association of bcl-2 immunopositivity with improved prognosis of non-small cell lung cancers (NSCLC) is controversial. Although two studies have reported better survival in bcl-2-immunopositive NSCLCs, a third series has contradicted this finding. The authors studied a relatively larger case series involving 427 patients for whom detailed information on long-term follow-up was available to determine the prognostic significance of bcl-2 expression. The study included 252 adenocarcinomas (AC), 111 squamous cell carcinomas (SCC), and 64 large cell carcinomas (LC). After antigen retrieval, sections were immunostained using a monoclonal anti-bcl-2 antibody (1:60, Clone 124, Dako) and the avidin-biotin complex technique. Staining was scored as positive or negative and also on a semiquantitative scale as 0, low (<10%), moderate (10% to 75%), or extensive (>75%). Bcl-2 immunoreactivity was correlated with survival using the actuarial survival method, Kaplan-Meier method, and log-rank test and was not associated with statistically significant differences in survival for NSCLCs (P = .5537). Differences in survival remained insignificant even after NSCLCs were stratified for cell type, stage, or grade, singly or in combination. Therefore, using this method, bcl-2 immunopositivity does not appear to act as an independent prognostic indicator in NSCLCs.

Fas receptor is expressed in human lung squamous cell carcinomas, whereas bcl-2 and apoptosis are not pronounced: a preliminary report

We report a pilot study on the Fas receptor (APO-1, CD95) in vivo in 15 human squamous cell (non-small) carcinomas and ten normal bronchial specimens. The principal aim was to investigate whether the so-called death receptor, Fas, is present in these tumours. Ligation of Fas promptly induces apoptosis, particularly in T Jurkat cells in vitro, and expression of Fas on human cancer would thus theoretically be of great interest. The immunoreactivity for the anti-apoptotic protein Bcl-2 was also investigated, and the degree of apoptosis was evaluated by TdT dUTP nick end labelling (TUNEL) and conventional morphological criteria. Fas was present in all initial tumours but absent in control tissue, that is in the potential precursor cells of bronchial epithelium (P = 0.001). Fas was not detectable after radiotherapy (P = 0.03). We propose that radiotherapy induces an early selection of tumour cells rather than a down-regulation of Fas. Both Bcl-2 and apoptosis (TUNEL) were generally expressed at a modest level. In agreement with other studies, we did not find any significant correlation between Bcl-2 and prognosis, or between Bcl-2 and TUNEL. Hence, in this preliminary report, we have demonstrated Fas receptor in human squamous cell carcinomas in vivo. This is a novel finding, and the apparent absence of Fas after radiotherapy may have important therapeutic implications.

bcl-2 oncoprotein in surgically resected non-small cell lung cancer: possibly favorable prognostic factor in association with low incidence of distant metastasis

BACKGROUND

The bcl-2 oncoprotein serves a regulatory function in permitting several cell types to die in an apoptotic process. Its overexpression probably plays a role in tumorigenesis and tumor development. The aim of this study was to determine the clinicopathological and prognostic significance of the bcl-2 oncoprotein in patients with nonsmall cell lung cancer (NSCLC).

METHODS

Immunostaining for bcl-2 oncoprotein was performed on 182 operable NSCLCs.

RESULTS

Thirty-six patients (19.8%) showed a positive immunostaining for bcl-2 oncoprotein. Histologically, its incidence was higher in squamous cell carcinomas (29.6%). Its expression status was inversely correlated with tumor development-associated parameters such as tumor stage in NSCLCs, especially in squamous cell carcinomas, bcl-2 positive patients with NSCLCs, especially squamous cell carcinomas, showed better overall survival and disease-free survival (DFS). In a multivariate analysis, this oncoprotein status had prognostic value in DFS for NSCLCs and in overall survival for squamous cell carcinomas. The recurrence of bcl-2 positive NSCLCs was significantly uncommon in distant extrathoracic organs.

CONCLUSIONS

The expression of bcl-2 oncoprotein in NSCLCs may be an early event of tumor development, especially in squamous cell carcinomas, and may be of importance in determining tumor progression and prognosis.

bcl-2 expression and prognosis in squamous-cell carcinomas of the esophagus

The bcl-2 proto-oncogene is a known inhibitor of apoptosis and may be an important regulator of tumor growth. In the present study, bcl-2-protein expression was investigated by immunohistochemistry and correlated with prognosis in a series of 150 potentially curatively resected squamous-cell carcinomas of the esophagus. For comparison, bcl-2-protein expression was analyzed in normal esophageal mucosa, severe squamous dysplasias and carcinomas in situ. bcl-2 immunoreactivity was found in 40 out of 150 invasive squamous-cell carcinomas; the remaining carcinomas were completely negative. bcl-2-protein expression was found more frequently among poorly differentiated than among well-differentiated tumors (p < 0.0001). No correlation was found between bcl-2-protein expression and the parameters tumor size, depth of invasion and nodal status. Moreover, bcl-2-protein expression had no significant influence on overall survival. Whereas in normal mucosa bcl-2 immunoreactivity was restricted to the basal-cell layer, in 9 out of 15 severe squamous dysplasias and in 7 out of 14 carcinomas in situ bcl-2 staining was detected in all epithelial layers. Thus, bcl-2-protein is frequently expressed in invasive squamous-cell carcinomas of the esophagus and in precursor lesions of esophageal cancer, but has no significant impact on the outcome of esophageal cancer.