Relationship between p53 gene abnormalities and other tumour characteristics in breast-cancer prognosis

Prognostic significance of Ki-67 and topoisomerase IIalpha expression in infiltrating ductal carcinoma of the breast. A multivariate analysis of 863 cases

To evaluate the prognostic relevance of Ki-67 and topoisomerase IIalpha expression in relation to tumor stage, grade, and hormone receptor content, 942 ductal infiltrating carcinomas of the breast were examined by means of the monoclonal antibodies Ki-S11 (Ki-67) and Ki-S4 (topoisomerase IIalpha). pS2, c-erbB2, and p53 were additionally considered as prognostic variables. The median follow-up time was 149 months. Eight-hundred-and-sixty-three tumors reacted with Ki-S11 and Ki-S4; the labeling indices of the two antigens were closely associated (r = 0.93). Both correlated positively with the tumor size, c-erbB2, and p53 expression, and negatively with patient age, hormone receptor content, and pS2 immunostaining. In the univariate analysis, Ki-S11 and Ki-S4 scores, nodal status, tumor size, tumor grade, and progesterone receptor content strongly predicted both overall and metastasis-free survival (p < 0.00001). Estrogen receptor status, p53, and c-erbB2 were of minor significance. Concerning overall survival, multivariate Cox regression analysis selected a Ki-S4 score >25% (p < 0.00001) next to the nodal status, and before tumor size, progesterone receptor content, and patient age. Independent predictors of the occurrence of distant metastases were nodal status, Ki-S4, tumor size, grade 1, and progesterone receptor negativity, in that order. The Ki-S11 score was of independent prognostic significance only if examined as a continuous variable. We conclude that topoisomerase IIalpha expression as assessed by monoclonal antibody Ki-S4 may add valuable information to current prognostic models for breast cancer. Its predictive value appears to be essentially related to the proliferative activity of tumor cells.

Prognostic and predictive value of p53 and p21 in breast cancer

The prognostic and predictive value of p53 has been extensively studied in breast cancer. p53 serves a multifunctional role as a transcriptional regulator, genomic stabilizer, inhibitor of cell cycle progression, facilitator of apoptosis, and also perhaps an inhibitor of angiogenesis. Abrogation of its function should therefore lead to a more aggressive breast cancer phenotype and a worse clinical outcome, and indeed the preponderance of studies confirm this, with the risk of recurrence and death increasing by 50% or more if p53 is abnormal. Lack of unanimity of results may be due to differences in technique, study design, or population, as well as the subjectivity inherent in some approaches; however, the complexity and random nature of genomic change present in cancer cells may well also contribute to the lack of unanimity. Because many anticancer agents may exert a therapeutic effect through genomic damage and subsequent triggering of apoptosis, and because p53 can respond to genomic damage and facilitate apoptosis, it can be hypothesized that an intact p53 would predict sensitivity to therapy. Present data in breast cancer, however, does not clearly indicate that this is the case. There are several potential explanations. Study designs to accurately test the predictive value of a molecular marker are more exacting and difficult to achieve than prognostic studies. There may also be multiple alternative pathways, not involving p53, that play a part in determining the therapeutic effect of a treatment. The prognostic value of a downstream effector of p53 has also been assessed, though less extensively. p21 is transcriptionally upregulated by p53 and is an inhibitor of cyclin-dependent kinases and thus of cell cycle progression. Higher levels of p21 might indicate a more indolent type of breast cancer. However, data from a number of clinical studies is very conflicting, and at present p21 is not a promising prognostic factor in breast cancer.

Correlation between p53, c-erbB-2, and topoisomerase II alpha expression, DNA ploidy, hormonal receptor status and proliferation in 356 node-negative breast carcinomas: prognostic implications

Various new prognostic indicators have been identified for mammary carcinomas, but the issue of their significance remains unsettled. The prognostic impact of p53, c-erbB-2, and topoisomerase II alpha expression was investigated in relation to standard prognostic factors for carcinomas of the breast and to the tumour cell growth fraction. Paraffin-embedded specimens of 356 node-negative infiltrating ductal carcinomas were stained immunohistochemically using a polyclonal antiserum to c-erbB-2, and the monoclonal antibodies DO-1 (p53), Ki-S4 (topoisomerase II alpha), and Ki-S5 (Ki-67). The patients were followed for a median duration of 99 months. Both p53 and c-erbB-2 were significantly associated with high tumour grade, large tumour size, DNA aneuploidy, lack of steroid hormone receptors, young age, and increased topoisomerase II alpha and Ki-67 expression levels. The correlation of p53 and c-erbB-2 was not significant. Topoisomerase II alpha and Ki-67 scores closely paralleled each other, indicating that both reflect the proliferative activity of tumour cells. A univariate analysis of overall (OS), specific (SS), and disease-free survival (DFS) revealed all the above-mentioned parameters to be statistically significant except patient age, which was relevant only to overall survival. Multivariate analysis with inclusion of all covariates selected tumour size and proliferation (topoisomerase II alpha and Ki-67) indices as independent predictors of survival in all three models. No additional information was gained by p53 or c-erbB-2. It is concluded that the proliferative activity, as assessed by topoisomerase II alpha or Ki-67 immunostaining, is the most useful indicator of breast cancer prognosis, except for tumour size.

MIB-1 labelling index is an independent prognostic marker in primary breast cancer

The proliferative activity of a tumour is considered to be an important prognostic factor in primary breast cancer. We have investigated the prognostic value of the MIB-1 labelling index in 341 patients with primary breast cancer and compared the results with the S-phase fraction in 220 patients of the same cohort. All patients were treated in one hospital and had a median follow-up of 128 months. No correlation between MIB-1 labelling and S-phase fraction could be demonstrated. MIB-1 had prognostic value for disease-free survival in the whole group of patients (P < 0.001) and in the node-negative subgroup (P < 0.001). In multivariate analysis, MIB-1 was an independent prognostic factor (P = 0.004) besides axillary lymph node status (P = 0.001). In univariate analysis high S-phase fraction was associated with decreased overall survival (P = 0.04); however, not in multivariate analysis. Moreover, S-phase fraction had a borderline prognostic significance for post-relapse survival in multivariate analysis (P= 0.08). Thus, in conclusion, the growth fraction of a tumour as determined by the MIB-1 labelling index is an important prognostic factor in patients with primary breast cancer.

Breast carcinoma in women under the age of 50: Relationship between p53 immunostaining, tumour grade, and axillary lymph node status

There is evidence to suggest that breast carcinoma in young women behaves in a more aggressive manner than in older women. As positive immunostaining for p53 has also been associated with increased tumour aggressiveness, this study was aimed at finding out whether patients under the age of 50 years have a higher prevalence of p53 positivity in their tumours. The inter-relationships between age, p53, tumour grade, and axillary lymph node status were also investigated. Two hundred and twenty nine invasive carcinomas were studied. One hundred and eight patients were under the age of 50, and 121 were at or above that age. The specific p53 monoclonal antibody DO7 and the avidin-biotin complex immunoperoxidase technique were used. Fifty seven tumours (25 %) showed variable degrees of p53 positivity. The incidence of positivity was slightly higher in women under the age of 50 as compared with those at or above that age (29% (31/108) vs. 21% (26/121), respectively), but the difference was not statistically significant (p < 0.05). On the other hand, in invasive ductal carcinoma (191 cases), p53 positivity was significantly related to high tumour grade (7% in grade I [1/14], 19% in grade II [20/105], and 43% in grade III [31/72]; p < 0.0001 [I-II vs III]). p53 positivity was also significantly related to the presence of extensive (more than three) axillary lymph node metastases (p53 positivity being 22% in node negative tumours [40/178], 18% in tumours with three or less positive nodes [6/33], and 61% in tumours with more than 3 positive nodes [11/18]; p = 0.0033 [second vs third group]). Both features were also significantly more common in the younger age group. The results suggest that the slightly higher incidence of p53 positivity seen in tumours from younger patients, is probably related to the significantly higher incidence of grade III tumours in these patients.

Tumor microvascularity has no independent prognostic significance for breast cancer

There is a continuing controversy regarding the value of estimating degree of intra-tumor vascularity to predict prognosis in breast cancer. In order to resolve this controversy, primary tumors from a cohort of 519 women with breast cancer were analysed to determine whether association exists between degree of vascularity and prognosis. Tumor vascularity was estimated by immunohistochemistry using a monoclonal antibody to the antigen CD31. The tumor area showing the highest degree of vascularity was chosen to score the number of microvessels per unit area. Issues such as the reproducibility of the microvascularity score and its association with tumor parameters including size, histological grade and hormone receptor levels were investigated. Although previously agreed criteria were used, consensus between two pathologists' estimations of the degree of vascularity was only moderate. There was no statistically significant association between tumor vascularity score and other currently established parameters of prognosis. After a median follow up of 71 months for axillary node negative patients, there was no association between tumor vascularity score and increased risk of relapse or death from breast cancer. In axillary node positive patients, tumor vascularity score was associated with increased risk of relapse and death from breast cancer. This association was not however independent of other established parameters of prognosis.

Immunofluorometrically determined p53 accumulation as a prognostic indicator in Italian breast cancer patients

The prognostic value of p53 protein accumulation in breast cancer, especially as detected by methods other than immunohistochemistry, has not been established unequivocally. A sensitive immunofluorometric assay of p53 protein employing DO-1 and CM-1 antibodies was used in this study to assay extracts of 171 breast carcinomas from northern Italy. p53 over-expression, demonstrated in 36 (21%) tumours, was associated with lack of oestrogen receptor (ER) expression but was not related to patient age, stage, lymph node status, tumour size, histologic type, grade or progesterone receptor (PR) expression status in contingency tables. An increased risk for cancer relapse of p53-positive patients compared to p53-negative patients was determined using multivariate Cox regression analysis, which also showed that p53 protein over-expression was an independent predictor of reduced disease-free survival in node-positive and ER+ patients but not in node-negative or ER- individuals. The equivalent analysis for assessing the impact of p53 status on overall survival was not statistically significant, possibly reflecting the short patient follow-up. Our results suggest that an immunoassay of p53 protein, applicable to cytosolic extracts prepared for steroid hormone receptor analyses, may provide information for breast cancer prognosis.

No significant predictive value of c-erbB-2 or p53 expression regarding sensitivity to primary chemotherapy or radiotherapy in breast cancer

To document whether c-erbB-2 over-expression or p53 accumulation in tumour cells was predictive of response to chemo- or radiotherapy, we analyzed a population of patients with breast cancer assigned to neo-adjuvant therapy (median follow-up: 54 months). T2/T3-N0N1b-M0 tumours (329 cases) were treated either by FAC chemotherapy or by radiotherapy before surgery, and the clinical response was classified as complete or incomplete. Expression of c-erbB-2 and p53 was retrospectively evaluated by immunohistochemistry. Proliferation rate was assessed by means of MIB-1 antibody and by S-phase fraction. A complete response to chemotherapy was observed in 38/167 patients (23%). Complete response rate was 20% in c-erbB-2-negative tumours, and rose to 31% in tumours with c-erbB-2 over-expression, but this trend was not statistically significant. There was no correlation between p53 staining and response to treatment, whereas chemosensitivity was found correlated with histological grade and S-phase. A complete response to radiotherapy was observed in 64 of the 156 evaluable patients (41%). Complete response rate was 41% in c-erbB-2- or p53-negative tumours, 54% in tumours with c-erb-B-2 over-expression, and 44% in tumours with p53 accumulation. There was no correlation between response to radiotherapy and histological grade or proliferative rate. No prognostic value was found for c-erbB-2 or p53 expression, whereas the 5-year survival rate was 85% for patients presenting a tumour with a low proliferating index (MIB-1 < 10%), and 68% for patients presenting a tumour with a high proliferative index. In multivariate analysis, node status (RR = 2), MIB-1 immunostaining (RR = 2), and tumour size (RR = 1.8) were found to be associated with survival. These results indicate that c-erbB-2 or p53 expression is not significantly associated with tumour response to neo-adjuvant chemo/radiotherapy in our series of breast cancers.

Detection of p53 gene mutation by rapid PCR-SSCP and its association with poor survival in breast cancer

We examined the association between mutation of the p53 gene and survival in a large cohort of breast cancer patients. Using a rapid, non-isotopic single-strand conformation polymorphism (SSCP) method we screened for mutations in exons 4-10 of the p53 gene in 375 primary breast cancers from patients with a median follow-up of 57 months. Mutations were found in 19% of tumours. Statistically significant associations were found between p53 mutation and histological grade, hormone receptor status, ploidy and S-phase fraction. No association was found between p53 mutation and axillary lymph node involvement, histological type, tumour size, vascular invasion or patient age. In univariate survival analysis, p53 mutation was strongly associated with poor prognosis. This was maintained in the lymph node-negative and hormone receptor-positive patient subgroups. In multivariate analysis, p53 mutation was associated with poor survival independent of lymph node status, estrogen receptor status and S-phase fraction. Our results demonstrate the feasibility of using a rapid and simple polymerase chain reaction-SSCP screening procedure to detect p53 gene mutation in breast cancer for the provision of prognostic information.

The cell cycle in breast cancer

Breast cancer is a heterogeneous disease regarding morphology, invasive behavior, metastatic capacity, hormone receptor expression and clinical outcome. For prediction of prognosis, tumor cell kinetics is an important feature, traditionally evaluated by estimation of cell growth-associated parameters such as mitotic index, S-phase fraction and expression of proliferation coupled proteins, for example proliferating cell nuclear antigen (PCNA) and Ki-67 antigen. Recent data indicate that deregulation of the cell cycle can occur at different levels in cancer and that the "deregulation pattern" can be of clinical significance. In the present overview we give a short description of approaches used for cell proliferation assessments, whereafter more recent data on cell cycle deregulation are discussed. Alterations of importance in breast cancer include overexpression of cyclins D1 and E, down-regulation of cyclin-dependent kinase inhibitors, such as p16, and inactivation of the retinoblastoma and p53 tumor suppressor proteins.

p53 exon 5 mutations as a prognostic indicator of shortened survival in non-small-cell lung cancer

Inactivation of the tumour-suppressor gene p53 has been described as one of the most common molecular changes found in lung tumours. Our purpose was to study the prognostic value of p53 alterations and to determine whether some specific mutation type in the p53 gene could be associated with poor clinical evolution in non-small-cell lung cancer (NSCLC) patients. To this end, we studied 81 resected primary NSCLCs in order to detect p53 alterations. p53 protein accumulation was analysed using immunohistochemistry methods; p53 gene mutations in exons 5-9 were studied using polymerase chain reaction-single-strand conformation polymorphism and sequencing techniques. p53 protein was immunodetected in 46.9% of lung carcinomas and 44.7% of p53-immunopositive tumours showed p53 mutations. Survival analysis was performed on 62 patients. No survival differences were found for patients with or without p53 immunopositivity. A shorter survival was found in patients with underlying p53 gene mutations, mainly in patients with squamous cell lung tumours; the worst prognosis was found when mutations were located in exon 5 (P = 0.007). In conclusion, the location of p53 mutations might be considered as a prognostic indicator for the evaluation of poor clinical evolution in NSCLC patients.

Vimentin expression is not associated with poor prognosis in breast cancer

The clinical significance of vimentin intermediate filament (VIF) expression was studied in relation to other established prognostic parameters in primary breast cancer. Archival tumour samples embedded in paraffin were examined by immuno-histochemistry with monoclonal antibodies (MAbs) to VIF, p53 protein and cell proliferation marker MIB-I. The vimentin staining pattern was heterogeneous, but in vimentin-positive areas > 80% of the tumour cells were positive. There was no association between vimentin expression and tumour size or the number of axillary lymph nodes involved. Vimentin expression was significantly associated with high-grade tumours, absence of hormone receptors, increased p53 expression and high tumour proliferation fraction as estimated by MIB-I count. Despite these associations with several recognised features of tumour aggressiveness, vimentin expression was not associated with increase in risk of relapse or death from breast cancer.