Prognostic value of bcl-2 oncoprotein expression in stage II colon carcinoma

The bcl-2 proto-oncogene encodes a Mr 25,000 protein that has been shown to prevent apoptosis or programmed cell death. The bcl-2 protein is detectable in basal cells of normal colonic epithelium, and an altered topographic distribution of this protein is found in colonic neoplasms. However, the clinical significance of abnormal bcl-2 expression in colon carcinomas remains unknown. We examined the prognostic value of the bcl-2 protein in TNM stage II colon carcinomas and its relationship to DNA ploidy, cell proliferation indices, p53 expression, and clinicopathological features. We analyzed 119 resected and otherwise untreated, paraffin-embedded stage II colon carcinomas for bcl-2 and p53 protein expression using immunohistochemistry. DNA ploidy and proliferative index (% S-phase + % G2-M) were determined by flow cytometry, and tumor grade and vascular microinvasion were assessed on histological sections. Cytoplasmic expression of the bcl-2 protein was detected in 72 (66%) of 110 carcinomas, and a high level of expression was significantly correlated with diploid DNA content (P = 0.02) and low proliferative activity (P = 0.005). bcl-2 was not associated with nuclear p53 expression. In a univariate analysis, a higher fraction of bcl-2-positive tumor cells was associated with better relapse-free survival (P = 0.02) and overall survival (P = 0.05) rates. Moreover, a high level of bcl-2 expression was an independent predictor of better relapse-free survival (P = 0.04), but not overall survival (P = 0.14), after adjustment for other variables, including proliferative index, DNA ploidy, and race. In conclusion, bcl-2 overexpression is associated with favorable prognostic features and may predict clinical outcome in stage II colon carcinomas.     

A phase II trial of weekly infusional 5-fluorouracil in combination with low-dose leucovorin in patients with advanced colorectal cancer

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunostaining. p53-negativity was noted in 40 cases and the remaining 19 tumours were p53-positive. Thirty-six tumours showed strong expression of bcl-2 and in 23 no staining for this protein was observed. We found statistically significant reverse correlation between expression of p53 and bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 53 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 (mean: 14.6). In these 53 cases we found that bcl-2-positive tumours were characterized by lower proliferation than bcl-2-negative tumours, the mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectively. p53-negative tumours showed lower proliferation than p53-positive tumours: mean Ki-67 index was 10.2% and 23.9%, respectively. We conclude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunostaining).     

p34cdc2 in invasive breast cancer: relationship to DNA content, Ki67 index and c-erbB-2 expression

AIMS: One-hundred and eighty-eight cases of human mammary carcinoma were examined immunohistochemically for their expression of Ki67, p34cdc2 and c-erbB-2. DNA image cytometry was performed to evaluate DNA ploidy, Auer type, S-phase fraction (SPF), 5c exceeding rate (5cER) and 2c deviation index (2cDI). METHODS AND RESULTS: One-hundred and sixty-eight cases were invasive ductal carcinomas, 20 were of invasive lobular type. Routinely assessed oestrogen and progesterone receptor scores were available. The results were analysed statistically in comparison to tumour type, histopathological grade, lymph node status, menopausal status, patient age and overall survival. Ki67 (P < 0.002) and c-erbB-2 (P < 0.0001) correlated well with overall survival (P < 0.0008) and grade (P < 0.038) but not with lymph node status and tumour type. p34cdc2 showed a trend towards a positive correlation with Ki67 (P < 0.058) and a significant negative correlation with receptor status (P < 0.008) but with none of the other parameters examined. CONCLUSIONS: No association between the DNA measured parameters (Auer type, SPF, 5cER and 2cDI) and survival was found. Our results suggest that c-erbB-2 and Ki67 are parameters which might, in combination with receptor status, help to define subgroups with different outcomes.     

Aberrant cytoplasmic expression of the p16 protein in breast cancer is associated with accelerated tumour proliferation

The p16 protein plays an important role in the transition of cells into the G1 phase of the cell cycle. We have studied the prevalence of p16 protein expression in breast carcinomas in a prospective series of 368 invasive and 52 non-invasive malignancies, as well as in 88 locally recurring tumours and three tumour cell lines. p16 protein expression was evaluated immunohistochemically on paraffin sections using monoclonal and polyclonal anti-p16 antibodies, and by immunoblotting of tumour cell suspensions. Tumour cell lines were also subjected to polymerase chain reaction-single strand polymorphism (PCR-SSCP) analysis and direct DNA sequencing. The results were compared with established prognostic parameters, DNA flow cytometry and p53 protein expression. In 33 (9%) invasive and two (4%) intraductal carcinomas, a cytoplasmic accumulation of the p16 protein was seen. These cases were characterized by poor histological grade of differentiation, loss of of oestrogen receptors and progesterone receptors and frequent overexpression of the p53 protein. In addition, breast carcinomas with aberrant p16 expression demonstrated a high proliferative activity, with median S-phase fractions 74% higher than in the control group and the median Ki67 fractions elevated to 75%. A genetic alteration of the p16 gene was not detectable in three analysed cell lines with cytoplasmic p16 expression applying PCR-SSCP and direct DNA sequencing. These results indicate that cytoplasmic accumulation of the p16 protein identifies a subset of highly malignant breast carcinomas with accelerated tumour proliferation and other unfavourable parameters in breast cancer. The described protein accumulation is apparently not caused by an alteration of the p16 gene.     

DNA ploidy in early gastric carcinoma (T1): a flow cytometric study of 100 European cases

DNA ploidy of 100 early gastric carcinomas (T1) was analysed by flow cytometry on archival material from five European centres and was correlated to morphological features and clinical behaviour. Tumours were classified according to the macroscopic appearance, histological type, and growth pattern. Aneuploidy was observed in 39% of tumours. Aneuploidy was more frequent in submucosal than in mucosal tumours (p = 0.04), in raised than in flat or ulcerated lesions (p = 0.001), and in the intestinal histological than in the diffuse types (p = 0.016). The presence of lymph node metastasis in 10 cases had no obvious relation to DNA ploidy. Five related deaths occurred during the follow up (6 months--16 years) of 84 patients. These results are similar to those reported in a large Japanese series suggesting no major differences between the two populations. Although follow up data were insufficient to relate DNA ploidy to tumour behaviour in this study, the Japanese experience shows that particular attention should be paid to early direction and complete surgical excision of raised intestinal type T1 carcinomas that have a Pen A growth pattern and are aneuploid.     

P53 protein expression and DNA ploidy in common epithelial tumors of the ovary

OBJECTIVE: To investigate p53 protein expression and DNA content in imprints from surgical biopsies of common epithelial tumors of the ovary. STUDY DESIGN: The study was based on 60 cases of epithelial tumors of the ovary (15 benign, 3 border-line and 42 malignant). For the demonstration of p53 protein, immunocytochemical staining with the avidin-extravidin technique was performed using monoclonal antibody p53 DO-7. DNA content was measured by image cytometry after Feulgen staining. RESULTS: There was a strong correlation between p53 expression and aneuploidy, with the difference between diploid and aneuploid tumors statistically significant (P < .001). A correlation was found between DNA ploidy, histologic grade and clinical stage (P < .001 and P < .05), respectively. There was no correlation between DNA ploidy and histologic type (P = .89). No correlation was observed between p53 protein expression and grade or clinical stage of the tumors. Nevertheless, a correlation of p53 expression between early (I, II) and advanced stages (III, IV) (P < .05) was observed. All benign and borderline tumors were diploid and did not express p53 protein. CONCLUSION: The results of the present study and the data in the literature stress the value of p53 expression and DNA ploidy in assessing the malignant potential of common epithelial ovarian cancers. However, the clinical application of these data requires further study.     

Mitochondrial DNA in idiopathic cardiomyopathy

143 women treated in 28 departments from 1980 to 1995 were retrospectively analysed to study the impact of prognostic factors in primary carcinoma of the fallopian tube. The mean age of the patients was 62.5 years. Sixty (42%) tumours were FIGO stage I, 28 (20%) stage II, 38 (27%) stage III, 17 (12%) stage IV. Complete radical resection was achieved in 102 (71%) patients. In 122 (85%) women, surgery involved removal of the uterus, the adnexa, and/or the omentum or lymph nodes. Postoperative therapy consisted of either irradiation (n = 40; 28%) or chemotherapy (n = 70; 49%); 33 women (23%) did not receive any treatment after surgery. The 5-year survival rate for all cases was 43%. The 5-year survival rate was 59% for stages I and II and 19% for stages III and IV (P < 0.00001). FIGO stage, histological grade and presence of residual tumour had an independent prognostic impact in multivariate analysis. In order to investigate the role of p53 in primary fallopian tube carcinomas, we analysed the immunohistochemical expression of p53 protein regarding survival and FIGO stage in 63 patients (44%). No statistical significance was observed.     

Expression of p53 protein has no independent prognostic value in breast cancer

A series of 392 female breast carcinomas was analysed immunohistochemically for expression of p53 protein with special emphasis on the role of p53 as an independent prognostic factor. Altogether, 54.8 per cent of the carcinomas expressed p53 protein, with the mean [standard error (SE)] fraction of positive nuclei being 17.1 per cent (1.2 per cent). Expression of p53 protein was independent of tumour metastasis at diagnosis, axillary lymph node status, tumour diameter, histological type, tubule formation, proportion of intraductal growth, margin formation, necrosis, DNA ploidy, and S-phase fraction. A high fraction of p53-positive nuclei was significantly related to patient age under 70 years, high grade, severe nuclear pleomorphism, dense infiltration of tumour by lymphocytes, high mitotic index, and high apoptotic index (for all, P < 0.05). Impaired survival probability in the entire cohort (P = 0.05) and in the axillary lymph node-positive (ANP) tumours (P = 0.015) was associated with a fraction of p53-positive nuclei less than 25 per cent, while in the axillary lymph node-negative (ANN) tumours, expression of p53 had no prognostic value. In multivariate analysis, independent prognostic predictors included axillary lymph node status, tumour diameter, and mitotic index. In the ANN tumours, tumour diameter, fraction of p53-positive nuclei, and tumour grade were independent prognostic factors, whereas in the ANP tumours, diameter and mitotic index were the two independent prognostic factors. The results suggest that abnormal expression of p53 protein is only a weak independent prognostic factor in female breast cancer.     

DNA amplifications at 20q13 and MDM2 define distinct subsets of evolved breast and ovarian tumours

DNA amplification seems to be particularly frequent in human breast tumours and has been associated with cancer evolution and aggressiveness. Recent data indicate that new events should be added to the list, such as the amplifications at chromosome 20q13 or the MDM2 gene. The present work aimed at determining the incidence and clinicopathological signification of these amplifications in a large series of breast and ovarian tumours. We tested 1371 breast and 179 ovarian tumours by Southern blotting and observed amplification of 20q13 in 5.4% breast and 2.8% ovarian carcinomas, whereas MDM2 was found amplified in 5.3% and 3.8% of breast and ovarian tumours respectively. MDM2 RNA expression levels were analysed in a subset of 57 breast tumours and overexpression was observed in 4/57 (7%) of the tumours. Elevated expression levels coincided with amplification of the gene. In breast cancer, 20q13 and MDM2 amplifications seem to define subsets of aggressive tumours. Indeed, 20q13 was correlated to axillary nodal involvement and occurred preferentially in younger patients (< 50 years). Furthermore, 20q13 correlated, as did MDM2 amplification, to aneuploidy. In parallel, we had also tested our tumour DNAs for amplification of CCND1, ERBB-2 and MYC, which made it possible to test for correlations with 20q13 or MDM2 amplifications. Whereas 20q13 showed a very strong correlation to CCND1 amplification, that of MDM2 was prevalent in MYC-amplified tumours. Interestingly, 20q13 and MDM2 amplifications showed some degree of correlation to each other, which may possibly be owing to the fact that both events occurred preferentially in aneuploid tumours. In ovarian cancer, no statistically significant correlation was observed. However, 20q13 amplification occurred preferentially in stage 3 tumours and MDM2 was correlated to ERBB-2 amplification. This may suggest that in ovarian tumours also, 20q13 and MDM2 amplifications occur in late or aggressive cancers.     

Automated and quantitative immunocytochemical assays of Bcl-2 protein in breast carcinomas

Expression of the bcl-2 gene was investigated in 218 human breast carcinomas by immunohistochemical analysis. Immunodetections were assessed using (1) frozen sections, (2) documented commercially available monoclonal antibody (bcl-2/124, Dako), (3) automation of immunoperoxidase technique (Ventana) and (4) quantitative evaluation of results by image analysis (SAMBA) and statistical analysis of quantitative data (BMDP software). Bcl-2 protein expression was correlated with current prognostic indicators and with molecular markers detected by the same procedure as for Bcl-2. It was shown that Bcl-2 expression is not related to patients' age, tumour size and type or lymph node status, but an inverse relationship was observed between Bcl-2 and tumour grade (P < 0.0001). An inverse relationship was also observed between Bcl-2 expression and p53 (P < 0.0001), Ki67/MIB1 antigen- (P = 0.0012), and P-gp- (P = 0.002) positive immunoreactions. In contrast, anti-Bcl-2 positive reaction was significantly associated with ER-positive (P < 0.001) and with ER/PR-positive or ER/PR/pS2-positive immunoreactions (P < or = 0.005). Bcl-2 expression was independent of CD31 and cathepsin D expression. Thus, Bcl-2 protein, thought to be antiapoptotic, exhibits parodoxical expression in human breast carcinomas. It is strongly detected in low-grade tumours (well-differentiated) with low (MIB1) growth fraction, but is independent of the tumour progression (size, node status, CD31, and cathepsin D). Bcl-2 acting on apoptosis is related to p53 gene abnormalities in breast carcinomas. Bcl-2 protein expression may also be involved in response to endocrine therapy (associated to ER/PR/pS2 positive immunoreactions) and probably with chemoresistance mechanisms (inverse relationship with P-gp).     

Immunohistochemical and mutational analysis of the p53 tumour suppressor gene and the bcl-2 oncogene in primary testicular germ cell tumours

The role of p53 in testicular germ cell tumours is still contradictory based on the finding of immunohistochemical overexpression at the protein level, but lack of mutations at the DNA level. In addition, p53 wild-type activity has been demonstrated in cell culture experiments. Overexpression of the proto-oncogene bcl-2 might block p53-induced apoptosis and might inhibit p53 functional activity. To clarify the apparent paradox with respect to p53 overexpression and lack of mutations, an immunohistochemical and mutational analysis of p53 and bcl-2 in TGCT was performed. Ten normal testes, 52 CIS and 151 clinical stage I nonseminomatous GCTs were included in our study. A commercially available anti-p53 polyclonal rabbit antibody and an anti-bcl-2-mouse monoclonal antibody were used to stain the 5pm sections. Staining was assessed by counting at least 500 cells from the area of the most intense staining in each tumour cell type, and this was scored semiquantitatively for intensity of staining on a 4 point scale. In addition, 30 primary GCTs were included in the mutational analysis: areas with p53 overexpression were identified and microdissected prior to DNA extraction. p53 exons 5-8 were amplified by polymerase chain reaction (PCR) followed by single strand conformation polymorphism analysis. Templates demonstrating band shifts on SSCP were subjected to direct DNA sequence analysis. None of the normal testes, 32/52 (62%) CIS, and 142/151 (94%) germ cell tumours exhibited p53 overexpression. p53 expression was significantly lower in mature teratomas (0.8 +/- 0.2) than in other germ cell tumour components (2.8 +/- 1.2, p > 0.001). PCR-SSCP did not reveal any missense mutations or deletions for the p53 gene. Bcl-2 protein expression was observed in none of the normal testes, in none of the CIS, and in 14/151 (9.3%) germ cell tumours. 13/14 germ cell tumours demonstrated bcl-2 expression only in the glandular and stromal elements of their teratomatous components whereas all other components were negative for bcl-2. Our results--p53 overexpression, lack of p53 mutations, undetectable bcl-2--are consistent with recent in vitro studies. High susceptibility of testicular cancer to drug-induced apoptosis appears to be the result of wild-type p53 and lack of bcl-2. Radiation and chemotherapeutic insensitivity of mature teratomas might be the result of bcl-2 overexpression and lack of p53 overexpression. Therefore, chemoresistance to DNA damaging agents might be reflected by the expression of p53 and bcl-2 and it might be useful to evaluate p53 and bcl-2 in primary tumours and metastatic lesions in order to identify patients early with primary or secondary chemoresistance.     

Old and new therapies for sporotrichosis

The bcl-2 gene encodes for a mitochondrial membrane proto-oncoprotein, the expression of which is known to suppress programmed cell death (apoptosis). In the present study the prognostic value of bcl-2 proto-oncoprotein was immunohistochemically investigated in a series of 104 colorectal carcinomas. The bcl-2 staining patterns were semiquantitatively assessed and correlated with the pTNM stage, Dukes' classification, lymphocytic infiltration (Jass classification) and tumour grade as well as parameters not associated with prognosis (gender, age, tumour site, histological tumour type). Statistical analysis was carried out using the Kaplan-Meier method, the log-rank test, hazard ratios and their confidence intervals. Fifty-five out of 104 cases completely lacked immunohistochemical bcl-2 expression. Fewer than 5% of bcl-2-positive cells were found in 25, 5-50% in 17 and more than 50% in five cases. The extent of bcl-2 expression by tumour cells decreased significantly with respect to increasing tumour size (P < 0.05), decreasing lymphocytic infiltration (P < 0.05) and chance of poor clinical outcome (P < 0.05), but not with worsening of Dukes stages. In multivariate analysis (Cox regression model) bcl-2 expression remained as an independent prognostic parameter with Dukes' classification as stratification factor (P < 0.001). Although the biological functions of bcl-2 protein are not yet well understood, our results provide further evidence that bcl-2 oncoprotein appears to be associated with favourable clinical outcome. Thus immunohistochemical bcl-2 phenotyping of colorectal carcinoma may contribute in future to the clinical management of these patients.     

Gastric cancer with p53 overexpression has high potential for metastasising to lymph nodes

Overexpression of the tumour suppressor gene p53 was investigated immunohistochemically in 96 primary gastric carcinomas and 26 corresponding metastatic perigastric lymph nodes. Abnormalities in p53 expression were found in 52 (54%) of the 96 primary carcinomas. Tumours stained positively for p53 frequently metastasised to lymph nodes (the metastatic rate: 85%) compared to findings in those with negative p53 staining (64%, P < 0.05). Ninety-two percent (24/26) of the malignant cells in the lymph nodes stained positively for p53. When the DNA ploidy pattern of the tumour was determined by flow cytometry, the aneuploid tumours in p53 positive and negative groups accounted for 69% and 45%, respectively (P < 0.05). Proliferative activity of the tumour, as measured by Ki-67 labelling, was significantly higher (30.6 +/- 12.0%) in the p53 positive group than that (25.1 +/- 10.7%) in the p53 negative group (P < 0.05). Thus, gastric cancer with a mutant p53 has high proliferative activity and metastasis to lymph nodes will probably occur.     

Neo-angiogenesis in locally advanced squamous cell head and neck cancer correlates with thymidine phosphorylase expression and p53 nuclear oncoprotein accumulation

Thymidine phosphorylase (Th.P) is an angiogenic factor shown to induce endothelial cell migration and proliferation. On the other hand, loss of wild type p53 function leads to down-regulation of thrombospondin-1, an inhibitor of angiogenesis. In this immunohistochemical study we investigated the intratumoural angiogenesis and thymidine phosphorylase (Th.P) expression in paraffin-embedded bioptical material from 104 locally advanced squamous cell head and neck cancers. The nuclear accumulation of mutant p53 protein and the cytoplasmic expression of bcl-2 protein was also assessed. High vascular grade was observed in 56% and high Th.P tumour cell reactivity in 48% of cases. High microvessel score was associated with an increased percentage of cancer cells expressing thymidine phosphorylase (P = 0.001). Increased p53 nuclear accumulation also correlated with high vascular grade (P = 0.001). High histological grade and absence of bcl-2 overexpression were associated with lymph node involvement (P = 0.002 and P = 0.02 respectively). No correlation of clinically detected lymphadenopathy with angiogenesis and p53 was observed. We conclude that intense neo-angiogenesis in locally advanced squamous cell head neck cancer is a frequent event, which is associated with nuclear p53 accumulation and thymidine phosphorylase overexpression.     

DNA ploidy, proliferative index and EGF-R status in 130 cases of resected gastric cancer--a multivariate analysis

BACKGROUND/AIMS: The purpose of this study was to define the prognostic role of DNA ploidy, proliferative index and EGF-R status in resected gastric cancer. MATERIALS AND METHODS: Ten clinico-pathological parameters and three biological factors obtained from flow cytometry and immunohisto-chemistry were evaluated in a series of 130 gastric cancer patients who received surgical treatment, including 28 stage IV cases (21.6%), using paraffin-embedded and fresh specimens in 77.7% and 22.3% of the cases, respectively. These variables were first analyzed and tested for correlation within the whole series and then weighted against survival in 117 applicable cases through univariate and multivariate analyses. RESULTS: Aneuploidy was significantly related to higher proliferative activity, EGF-R expression and deeper stomach wall infiltration. Higher proliferative activity was significantly related to deeper stomach wall infiltration and larger tumor diameter. The latter showed a significant relationship to EGF-R expression. Univariate analysis showed the significant variables for survival to be DNA ploidy, pT, pN, M, stage, histological type according to Lauren and tumor diameter. Multivariate analysis calculated on these significant variables using the Cox multiple stepwise regression model detected three factors which independently influence survival: pathological stage (p < 0.00001), histological type according to Lauren (p < 0.002) and DNA ploidy (p < 0.03). CONCLUSIONS: DNA ploidy was shown to be a significant prognostic parameter in resected gastric cancer after pathological stage and histological type according to Lauren. The prognostic roles of proliferative activity and EGF-R status require further investigation.     

bcl-2 and p53 immunophenotypes in pre-invasive, early and advanced oesophageal squamous cancer

AIMS: An inverse correlation between bcl-2 and p53 expression has been reported in several types of epithelial tumour. The role of bcl-2 and p53 in the development of oesophageal squamous carcinoma has yet to be established. The expression of bcl-2 and p53 proteins has been evaluated in the multistage oesophageal tumorigenesis, which progresses from normal mucosa to dysplasia (squamous intraepithelial lesion, SIL), to invasive early and advanced oesophageal squamous cancer. METHODS AND RESULTS: Sixty-four cases of squamous oesophageal cancer, coexisting with SIL in 18 cases, were immunohistochemically analysed for any overexpression of bcl-2 and p53 proteins. Any association of bcl-2 and p53 protein expression with patient survival was also analysed. We observed bcl-2 expression that decreased significantly during the progression of oesophageal carcinogenesis. A decreasing frequency in the expression of bcl-2 in advanced oesophageal squamous cancer coincided with frequent p53 overexpression. bcl-2 expression was correlated with patient survival by univariate analysis. The association disappeared after adjusting for tumour stage, p53 overexpression showed no association with patient survival by either univariate or multivariate analysis. CONCLUSIONS: The down-regulation of bcl-2 and upregulation of p53 in advanced oesophageal squamous cancer suggest that bcl-2 and p53 proteins may interact in the progression of oesophageal squamous cancer.     

Apoptosis and cancer chemotherapy

Cytotoxic drugs currently remain as the basis for the chemotherapy of metastatic cancer. Why they fail to kill sufficient tumour cells in the major human solid cancers, such as the carcinomas, is suggested in this review to be due to the inherent inability of these cells to engage apoptosis after drug-induced damage. As a paradigm for drug resistant cancers, the resistance of bladder carcinoma cell lines to DNA damaging drugs is described here in terms of their response to the topoisomerase II poison etoposide. 60%-70% of bladder carcinomas have mutant p53; this can prevent the detection of and response to DNA damage. In vitro studies with a bladder carcinoma cell line containing a wild type p53 showed that it underwent a G1 checkpoint after etoposide, potentially allowing DNA damage repair, as well as apoptosis. In lines with mutant or non-functional p53 there is no checkpoint and no apoptosis. All lines showed constitutive expression of bcl-2 and bcl-XL (the suppressors of apoptosis) with low and non-inducible levels of bax (a promoter of apoptosis). Taken together, this menu of gene expression is more favourable to survival than apoptosis after the imposition of drug-induced DNA damage and may contribute to their inherent drug resistance.     

Reduced expression of retinoblastoma gene product (pRB) and high expression of p53 are associated with poor prognosis in ovarian cancer

Paraffin sections (n = 168, 27 benign, 16 low malignant potential [LMP] and 125 malignant tumours) from epithelial ovarian tumours were evaluated immunohistochemically for expression of retinoblastoma gene product (pRB) and p53 protein, and the relationship among pRB, p53 and cyclin-dependent kinase inhibitor 2 (CDKN2) gene product p16INK4A (p16) was analysed, following our previous study of p16. Forty-one percent of the benign, 50% of the LMP and most (71%) of the malignant tumours showed high pRB expression. High expression of pRB (>50% pRB-positive cells) significantly correlated with non-mucinous histological subtypes. Reduced pRB expression, substage and residual disease were significant predictors for poor prognosis in stage I patients. All the benign and most of the LMP (81%) tumours were in either the p53-negative or low p53-positive category, but nearly half of the malignant tumours had high p53 expression. High p53 accumulation was found in non-mucinous, high grade and late stage tumours. For well-differentiated carcinomas, high p53 expression was a predictor of poor prognosis. However, even though high p53 expression was not associated with histological subtype, stage or the presence of residual disease, high p53 expression was not an independent predictor when all clinical parameters were combined. For all ovarian cancers, a close correlation was found between high p53 and high p16 expression. The relationship between the expression of pRB and p16 depended on tumour stage. In stage I tumours, high pRB was associated with low p16 reactivity. On the other hand, most advanced tumours showed both high pRB and high p16 reactivity.     

The prevalence of bcl-2, p53, and Ki-67 immunoreactivity in transitional cell bladder carcinomas and their clinicopathologic correlates

The aim of this study was to investigate the expression of bcl-2, p53 oncoproteins, and Ki-67 antigen in a series of transitional cell bladder carcinomas and its relation to the traditional prognostic indicators and patient's survival. One hundred six cases with transitional cell carcinoma (TCC) were examined for detection of bcl-2, p53 proteins, and Ki-67 antigen (MIB1 antibody). Bcl-2 immunohistochemical positivity was observed in 52% of TCCs and in 57% of low-grade and 44% of high-grade TCCs. Bcl-2 was also detected in normal urothelium and dysplastic lesions with basal cell expression, and negative staining was observed in carcinomas in situ. Tumor stage showed a significant inverse correlation with overall bcl-2 positivity. The loss of bcl-2 protein expression in higher-stage TCCs was statistically significant (Pt = .01). p53 protein was overexpressed in 50% of TCCs and more frequently in invasive and in carcinomas in situ than in superficial TCCs (Pt = .03). In contrast, detection of p53 was not observed in normal and dysplastic urothelium. p53 positivity was related to the degree of differentiation and to the stage of the disease (Pf = .01 and Pt = .03, respectively). Concerning Ki-67 antigen, its expression was found in 57.5% of TCCs. There was a strong overall correlation of Ki-67 with tumor stage (Pt = .002) and grade (Pf = .002). Univariate statistical analysis showed that the expression of p53 and Ki-67 was significantly correlated to poor prognosis (P = .02, P = .02, respectively). On multivariate analysis, none of these markers but only stage and grade were significantly correlated to prognosis (P = .02, P = .02, respectively). These findings suggest that overexpression of bcl-2 protein may be an early event in tumorigenesis. Tumors with loss of bcl-2 positivity and overexpression of p53 and Ki-67 had an unfavorable prognosis; however, in multivariate analysis, they had no independent prognostic value.     

Racial differences in clinically localized prostate cancers of black and white men

PURPOSE: Tumor grade, deoxyribonucleic acid (DNA) ploidy, proliferation, p53 and bcl-2 expression were examined in clinically localized prostate cancers of black and white American men to learn whether these features showed racial differences. MATERIALS AND METHODS: A total of 117 prostate cancers (43 black and 74 white patients) obtained at radical prostatectomy for clinically localized disease were assigned Gleason scores by a single pathologist. Enzymatically dissociated nuclei from archival prostate cancers were examined by DNA flow cytometry using propidium iodide staining and the multicycle program to remove debris and sliced nuclei and to perform cell cycle analysis. For immunostaining after microwave antigen retrieval we used a DO-1/DO-7 monoclonal antibody cocktail for p53 and the clone 124 antibody for bcl-2. RESULTS: Significantly more black than white men had Gleason score 7 tumors. The DNA ploidy distribution of Gleason 6 or less tumors was similar for both races. As anticipated, the ploidy distribution of higher grade prostate cancer in white men was more abnormal but, unexpectedly, this was not found for higher grade prostate cancer in black men. No significant racial differences were found in S phase fractions, p53 or bcl-2 immunopositivity. However, for prostate cancer in black men there was a significant association between bcl-2 immunopositivity and higher S-phase fractions. CONCLUSIONS: The aggressive prostate cancers of black men may be characterized by the 2 features of high proliferation and a block to programmed cell death.