Clinical relevance of immunohistochemical expression of p53-targeted gene products mdm-2, p21 and bcl-2 in breast carcinoma

Increased expression of senescence markers p14(ARF) and p16(INK4a) in breast cancer is associated with an increased risk of disease recurrence and poor survival outcome

AIMS

Breast cancer is a hormonally driven disease. Cellular senescence is an age-related irreversible cell cycle arrest at the G1 phase upon induction. The aim of this study was to characterize the expression patterns of the senescence markers p14(ARF) , p16(INK4a) and p21(WAF1/Cip1) during breast cancer progression in a large patient cohort.

METHODS AND RESULTS

We conducted a retrospective study of 1080 patients with invasive ductal carcinoma, no special type, over an 11-year period. We performed immunohistochemical staining on tissue microarrays that included normal, benign hyperplasia, ductal carcinoma in situ and invasive ductal carcinoma tissue from each patient. Invasive ductal carcinomas showed higher expression of p14(ARF) and p16(INK4a) but lower expression of p21(WAF1/Cip1) than non-malignant tissues. There were significant correlations of normal, benign, preinvasive and malignant tissues with p14(ARF) , p16(INK4a) and p21(WAF1/Cip1) expression (P < 0.05). Univariate comparison showed a correlation between high p16(INK4a) expression and poor survival (P = 0.000) and an increased risk of relapse (P = 0.000), whereas high p14(ARF) expression correlated only with an increased risk of relapse (P = 0.038). Multivariate analysis showed p16(INK4a) to be an important prognostic factor for overall survival (P = 0.011) and disease-free survival (P = 0.004), with p14(ARF) also being a significant prognostic factor for disease-free survival (P = 0.043). Moreover, patients showing both high p16(INK4a) expression and and high p14(ARF) expression had an adjusted three-fold increased risk of disease recurrence (P < 0.05) and a two-fold increased risk of all-cause-related death (P < 0.05).

CONCLUSIONS

These finding suggest p16(INK4a) expression and p14(ARF) expression may play an important role in the progression of proliferative breast tissue to invasive cancer, and may be useful as prognostic factors.

Fulvestrant treatment alters MDM2 protein turnover and sensitivity of human breast carcinoma cells to chemotherapeutic drugs

The human homologue of mouse double minute 2 (MDM2) is overexpressed in tumors and contributes to tumorigenesis through inhibition of p53 activity. We investigated the effect of the anti-estrogen fulvestrant on MDM2 expression and sensitivity of estrogen receptor positive human breast cancer cell lines to chemotherapeutics. Fulvestrant down-regulated MDM2 through increased protein turnover. Fulvestrant blocked estrogen-dependent up-regulation of MDM2 and decreased basal expression of MDM2 in the absence of estradiol. As combinations of fulvestrant with doxorubicin, etoposide or paclitaxel were synergistic, altering cell cycle distribution and increasing cell death, this provides rationale for testing combinatorial chemotherapy with fulvestrant as a novel therapeutic strategy for patients with advanced breast cancer.

gef gene expression in MCF-7 breast cancer cells is associated with a better prognosis and induction of apoptosis by p53-mediated signaling pathway

Breast cancer research has developed rapidly in the past few decades, leading to longer survival times for patients and opening up the possibility of developing curative treatments for advanced breast cancer. Our increasing knowledge of the biological pathways associated with the progression and development of breast cancer, alongside the failure of conventional treatments, has prompted us to explore gene therapy as an alternative therapeutic strategy. We previously reported that gef gene from E. coli has shown considerable cytotoxic effects in breast cancer cells. However, its action mechanism has not been elucidated. Indirect immunofluorescence technique using flow cytometry and immunocytochemical analysis were used to detect breast cancer markers: estrogen (ER) and progesterone (PR) hormonal receptors, human epidermal growth factor receptor-2 proto-oncogene (c-erbB-2), ki-67 antigen and p53 protein. gef gene induces an increase in ER and PR expressions and a decrease in ki-67 and c-erbB-2 gene expressions, indicating a better prognosis and response to treatment and a longer disease-free interval and survival. It also increased p53 expression, suggesting that gef-induced apoptosis is regulated by a p53-mediated signaling pathway. These findings support the hypothesis that the gef gene offers a new approach to gene therapy in breast cancer.

Significance of Her-2/neu protein over expression in Indian breast cancer patients

BACKGROUND

Racial disparity in presentation and outcome of breast cancer is established but cause is unexplained. Many studies show various molecular markers for racial differences in the prognosis of breast cancer. There is scarcity of data on prognostic significance of HER-2/neu in Indian breast cancer.

AIMS AND OBJECTIVE

To know incidence and prognostic significance of HER-2/neu expression in Indian patients. To correlate HER-2/neu Expression with other prognostic markers and ER/PR Receptor status.

MATERIAL AND METHODS

112 consecutive patients with breast cancer attending the Department of Surgical Oncology from March 1997 to March 2000 were included in this study. The clinical data along with ER/PR status, follow up data and HER-2/neu expression examined by immuno-histochemical method was recorded.

STATISTICAL ANALYSIS

Data was analyzed by univariate and multivariate analysis for all prognostic factors. Significance was calculated by using Chi square test and survival analysis by using Kaplan Meier survival curve.

RESULTS

The median age of 112 patients was 46.56 (±9.55) years. HER-2/neu over expression was present in 46.37%. Significant correlation was found between HER-2/neu over expression and lymph node status, grade of tumor and ER/PR receptor status. Median follow up period of 23 months. There was significant tumour free survival advantage (p < 0.01) and overall survival advantage (p < 0.001) in patients with HER-2/neu negative expression.

CONCLUSION

HER-2/neu oncogene over expression is higher (46.37%) among Indian patients in comparison to 25-30% shown in most western literature. HER-2/neu oncogene over expression significantly correlates with grade, lymph node involvement, ER/PR status and also affects survival.

Cell cycle related proteins in hyperplasia of usual type in breast specimens of patients with and without breast cancer

BACKGROUND

Hyperplasia of usual type (HUT) is a common proliferative lesion associated with a slight elevated risk for subsequent development of breast cancer. Cell cycle-related proteins would be helpful to determine the putative role of these markers in the process of mammary carcinogenesis. The aim of this study was to analyze the expression of cell cycle related proteins in HUT of breast specimens of patients with and without breast cancer, and compare this expression with areas of invasive carcinomas.

RESULTS

Immunohistochemical evaluation was performed using antibodies against cell cycle related proteins ER, PR, p53, p21, p63, and Ki-67 in hyperplasia of usual type (HUT) in specimens of aesthetic reduction mammaplasty (ARM), in specimens of mammaplasty contralateral to breast cancer (MCC), and in specimens of invasive mammary carcinomas (IMC) presenting HUT in the adjacent parenchyma. The results showed that the immunoexpression of ER, PR, p21, p53, p63, and KI-67 was similar in HUT from the three different groups. The p63 expression in myoepithelial cells showed discontinuous pattern in the majority of HUT, different from continuous expression in normal lobules. Nuclear expression of p53 and p21 was frequently higher expressed in IMC and very rare in HUT. We also found cytoplasmic expression of p21 in benign hyperplastic lesions and in neoplastic cells of IMC.

CONCLUSION

Our data failed to demonstrate different expression of cell cycle related proteins in HUT from patients with and without breast cancer. However, we found discontinuous expression of p63 in myoepithelial cells around HUT adjacent to carcinomas and cytoplasmic expression of p21 in epithelial cells of hyperplastic foci. Further studies are needed to determine how these subgroups relate to molecular abnormalities and cancer risk.

Relationship and prognostic significance of phospho-(serine 166)-murine double minute 2 and Akt activation in node-negative breast cancer with regard to p53 expression

The Akt signalling pathway plays a central role in tumourigenesis. Activation of Akt is related to a more aggressive phenotype in various human cancers, including breast cancer. Its activation contributes to cancer progression via pleiotropic effects, including suppression of apoptosis and modulation of cell cycle regulation. Murine double minute 2 (MDM2) is an oncoprotein that inhibits the function of p53 tumour suppressor protein. Cell culture studies show that Akt-related phosphorylation of MDM2 at serine 166 allows MDM2 to gain nuclear entry and fulfil its p53 regulating function. This study was designed to analyse the relationship of phospho-MDM2 (pMDM2) expression with Akt activation to determine a possible prognostic relevance of pMDM2 in node-negative breast cancer with respect to Akt activation and p53 status. pMDM2, phospho-Akt (pAkt) and p53 protein expression status were analysed immunohistochemically in 121 paraffin-embedded breast cancer cases. Expression of pMDM2 correlated with Akt activation (P<0.001). Univariate analysis identified pMDM2 as a prognostic factor (P=0.0458) in node-negative breast cancers. The unfavourable prognostic significance was even more pronounced in tumours with a pMDM2(+)/pAkt(+) immunophenotype (P=0.0205). Stratification into a p53-negative subgroup further strengthened the adverse prognostic influence. These data confirm that MDM2 phosphorylation at serine 166 is mediated by Akt kinase. Besides the prognostic impact of pMDM2, our findings suggest that Akt-mediated modulation of the MDM2/p53 complex contributes to increased tumour aggressiveness especially in p53-negative breast cancers. However, due to the relatively small number of patients in this cohort, the results obtained need to be confirmed by larger cohorts.

Flow cytometry and quantitative immunohistochemical study of cell cycle regulation proteins in invasive breast carcinoma: prognostic significance

BACKGROUND

Between January 11, 1991 and January 8, 1992, 104 patients with previously untreated, invasive, primitive breast carcinoma were admitted to the authors' hospital.

METHODS

For each patient, flow cytometry DNA analyses on frozen samples and on immunohistochemical staining were performed, including Ki-67, cyclin A, p53, and p21(waf1) (p21), with assessment of the percentages of positive nuclei were assessed. Correlations with classic clinicopathologic data and survival (overall, metastasis free, or recurrence free) and a multivariate analysis were performed.

RESULTS

After a multivariate analysis according to a Cox model that was stratified by age, tumor size, tumor grade, lymph node status, and receptor status, among the factors studied, the presence of p21 was the unique remaining prognostic factor for patients with invasive breast carcinoma. Because of the lack of a correlation between p21 and proliferative factors (Ki-67, S-phase, and cyclin A), the authors combined p21 with those markers and found that, for the different combinations, after statistical analysis, only p21 combined with S-phase or with cyclin A and lymph node status were salient survival prognostic factors.

CONCLUSIONS

Immunohistochemical study of proteins involved in the cell cycle and assessment of proliferative activity using flow cytometric DNA analysis aided the authors in singling out correlations of cyclin A and S-phase, along with p21, with metastasis free survival and overall survival in patients with invasive breast carcinoma. These promising results will require confirmation in a larger series of patients.

p21WAF1 expression in invasive breast cancer and its association with p53, AP-2, cell proliferation, and prognosis

AIMS

To evaluate the expression and prognostic relevance of p21(WAF1) in breast cancer and to investigate its association with p53, activator protein 2 (AP-2), and cell proliferation (as assessed by Ki-67 expression).

METHODS

p21(WAF1) expression was analysed immunohistochemically in a large prospective, consecutive series of 420 patients with breast cancer diagnosed and treated between 1990 and 1995 at Kuopio University Hospital, Kuopio, Finland. Inter-relations between p21(WAF1) expression and p53, AP-2, and Ki-67 were evaluated. The expression of p21(WAF1) was also compared with clinicopathological parameters and the patients' survival.

RESULTS

In general, nuclear p21(WAF1) expression was low in carcinomas (median, 2.5%; range, 0-70%). Expression was lowest in lobular carcinomas (chi(2) = 7.4; p = 0.025). p21(WAF1) positive tumours were more often p53 positive (chi(2) = 4.2; p = 0.041) but expression of p21(WAF1) did not correlate with AP-2 expression or Ki-67 in the whole patient group. In addition, the combined expression of p21 and p53 was not associated with AP-2 expression. High nuclear p21(WAF1) positivity (n = 160; 38%) was associated with poor differentiation (chi(2) = 8.1; p = 0.017). In the univariate analyses, p21(WAF1) expression had no prognostic value for predicting breast cancer related survival (BCRS) or recurrence free survival (RFS) in the whole patient group or in the subgroups investigated. However, in postmenopausal patients with lymph node metastases, and oestrogen receptor (ER) and/or progesterone receptor (PR) positive tumours, high p21(WAF1) expression predicted response to adjuvant hormonal treatment with antioestrogens. In the univariate analysis, the significant factors for predicting BCRS were Ki-67 expression, stage, lymph node status, histological grade, ER and PR status, and those for RFS were Ki-67 expression, stage, and lymph node status. In the multivariate analysis, the independent predictors of shorter BCRS were high cell proliferation activity measured by Ki-67 expression (p < 0.001), advanced stage (p < 0.001), and poor differentiation (p = 0.048). Shorter RFS was independently predicted by high cell proliferative activity (p < 0.001) and advanced stage (p < 0.001).

CONCLUSIONS

The regulation of p21(WAF1) seems to occur independently of p53 or AP-2 and analysing p21(WAF1) expression provided no prognostic information for patients with breast cancer.

Significance of p53, Bcl-2, and HER-2/neu protein expression in Omani Arab females with breast cancer

Racial disparity in the presentation of breast cancer and the outcome of its treatment is well established. However, the causes remain unexplained. The scarcity of reports about the prognostic significance of p53, bcl-2, and HER-2/neu in Arab females with breast cancer has been the impetus to this study. We evaluated the prognostic significance of altered expression of p53, bcl-2, HER-2/neu in Omani Arab females with non-metastatic breast cancer with correlation to other established prognostic factors. We have retrospectively analyzed the immunohistochemical expression of p53, HER-2/neu and bcl-2 in paraffin embedded blocks of 72 females diagnosed with invasive breast cancer between 1992 and 2002. The expression of the above proteins was correlated with other prognostic factors and univariate and multivariate analysis was carried out for all prognostic factors. Overexpression of p53 significantly correlated with younger age (<40), pre-menopausal status, poor differentiation with inverse correlation with bcl-2 expression. Expression of bcl-2 immunopostivity significantly correlated to low histological grade and positive estrogen and progesterone receptor status. On univariate and multivariate p53 overexpression and lack of bcl-2 immunostaining resulted in worse survival outcome, but not Her-2/neu overexpression. Expression patterns of p53 and bcl-2 are independent predictors of survival in Omani Arab population which may help to stratify these patients into different risk groups.

Correlations of Breast Carcinoma Biomarkers and p53 Tested by FASAY and Immunohistochemistry

p53 status is an important predictive factor in breast cancer, but the results of many studies are ambiguous. We tested p53 by functional analysis of separated alleles in yeast (FASAY) as well as by immunohistochemistry (IHC) and evaluated correlations with main prognostic factors, proliferation, and Bcl-2. Thirty-two tumors were tested with antibodies BP53-12, DO1, DO11, DO12, and by FASAY. Spearman rank correlations were tested separately with age, tumor type, pT, grade, pN, NPI, Ki-67, S-phase, proliferation index, Bcl-2, and steroid receptor status determined by ER, PR, and pS2. FASAY showed significant correlations with ductal type, grade and proliferation, and an inverse correlation with functional estrogen receptor and Bcl-2. FASAY provided better correlations compared to p53 IHC. We conclude that FASAY shows significant correlations with main prognostic/predictive factors and provides more reliable biological information compared to p53 IHC. Apoptosis is positively linked to proliferation and is not under the control of p53, which is frequently mutated in highly proliferating carcinomas. FASAY seems to be very important in assessing the predictive significance of p53 for a specific therapy of breast cancer.

Telomerase as a prognostic marker in breast cancer: high-throughput tissue microarray analysis of hTERT and hTR

Telomerase activity (TA) has been shown to correlate with poor clinical outcome in various tumour entities, indicating that tumours expressing this enzyme may be more aggressive and that TA may be a useful prognostic marker. For breast cancer, however, TA is a controversial prognostic marker; whereas some studies suggest an association between TA and disease outcome, others do not find this association. This study used tissue microarrays (breast carcinoma prognosis arrays) containing 611 samples (each 0.6 mm in diameter) from the tumour centre of paraffin-embedded breast carcinomas to analyse the catalytic subunit of telomerase, human telomerase reverse-transcriptase (hTERT), and the internal RNA component (hTR), which are the core components of the telomerase holoenzyme complex. hTERT protein expression was obtained by immunohistochemistry (human anti-telomerase antibody Ab-2, Calbiochem), and hTR RNA was measured by radioactive in situ hybridization. hTERT and hTR expression were determined semi-quantitatively and graded (scores 1-4). Clinical data, such as histological subtype, pT stage, tumour diameter, pN stage, BRE grade, tumour-specific survival (in months), patient's age and others, were available for statistical analysis. A statistically significant correlation was found between tumour-specific survival (overall survival) and hTERT expression (p < 0.0001) or hTR expression (p = 0.00110). Tumours with higher scores (scores 3, 4) for hTR and/or hTERT were associated with a worse prognosis. In multivariate analysis, hTERT expression was an independent prognostic factor. Previous studies, focusing on analysis of TA in smaller numbers of fresh-frozen breast carcinomas by the TRAP assay, gave controversial results with respect to TA as a prognostic marker. Using tissue microarrays from 611 breast carcinomas, this study has demonstrated that increased expression levels of the telomerase core components, hTERT and hTR, are associated with lower overall survival. These findings suggest that TA should be included in future validation studies as a prognostic marker in breast cancer.

Reduced expression of both Bax and Bcl-2 is independently associated with lymph node metastasis in human breast carcinomas

Imbalance between pro-apoptotic and anti-apoptotic proteins, causing altered apoptosis, may lead to tumour development and tumour progression, and reduced response to adjuvant therapy. In this study, we evaluated the expression patterns of Bcl-2, Bcl-xL, and Bax protein in 126 primary invasive breast carcinomas, and the association with other clinicopathological parameters. We used immunohistochemical methods to evaluate protein expression. Reduced expression of both Bax and Bcl-2 was associated with lymphnode metastases in univariate analyses (one-way ANOVA) as well as in multivariate analysis (binary logistic regression) (Bcl-2 p=0.003 univariate, p=0.01 multivariate, Bax p=0.05 univariate, p=0.03 multivariate). Bcl-2 overexpression showed an inverse association with cyclin A (p=0.05), while expression of Bcl-xL showed an association only with cyclin D3 (p=0.04). Bcl-xL expression also showed a highly significant association with oestrogen receptor status (p=0.009). Bcl-2 and Bcl-xL showed an association with different D-type cyclins, indicating different pathways of pathogenesis. Expression of Bcl-2 was associated with better patient survival in univariate analysis (Kaplan meyer p=0.04), but lost its prognostic value in multivariate analysis (Cox regression p=0.2).

p21 gene codon 31 arginine/serine polymorphism: non-association with endometriosis

p21, an important regulator of the cell cycle, acts as a mediator of the growth-suppressing and -promoting functions of p53. We aimed to investigate the association between codon 31 polymorphisms of p21 gene and endometriosis. Women were divided into two groups: endometriosis (n = 102) and nonendometriosis (n = 119). The gene polymorphism for p21 codon 31 involved a base change from AGC to AGA and amino acid changes from serine (Ser) to arginine (Arg). Polymorphisms (Ser homozygotes, heterozygotes, Arg homozygotes) between both groups were detected and compared. Associations between the endometriosis and polymorphisms were evaluated. The results revealed that the distributions of different p21 polymorphisms in both groups were nonsignificantly different. The proportions of Ser homozygote/heterozygote/Arg homozygote in endometriosis and nonendometriois populations were 26.5/48.0/25.5% and 17.6/50.4/31.9%, respectively. We concluded the noncorrelation between the endometriosis and the p21 codon 31 polymorphism. p21 gene codon 31 arginine/serine polymorphism is not a useful marker for prediction of endometriosis susceptibility.