Significance of Expression of p16, Cyclin D1, Rb, and p53 Protein and Correlation with Clinicopathologic Prognostic Factors in Invasive Ductal Carcinoma of the Breast

The retinoblastoma (Rb)/cyclin D1/p16 pathway is an important constituent of cell cycle regulation. Perturbations in this pathway due to a variety of genetic aberrations have been reported in many human cancers including breast cancer. We examined the significance of immunoexpression of p16 protein, cyclin D1 protein, Rb protein (pRb), and p53 protein in 128 cases of invasive breast carcinoma. The results were correlated with survival rate and clinicopathological variables, including age, histologic grade, lymph node status, tumor size, estrogen receptor (ER), and progesterone receptor (PR) content. Abnormal expressions of p16 and pRb which were defined as negative staining were seen in 21% and 43% of tumors, respectively. There was a significant inverse relationship between p16 and pRb expression. There was no correlation between p16 staining and any other parameters, including survival rate, cyclin D1, p53, and clinicopathologic variables. Surprisingly, there was a trend for tumors which were positive for pRb to be grade III ductal carcinomas. Cyclin D1 positivity was noted in 46% of cases. The expression of cyclin D1 protein was significantly higher in lower histologic grade, higher ER and PR expression. The expression of p53 protein showed a significant correlation with high tumor grade. In a Cox multivariate analysis, neither p16, pRb, cyclin D1 nor p53 was an independent predictor, but tumor size and lymph node status were independent predictors of patient outcome.

Correlation of Expression of CD44, p53 and bcl-2 Protein, DNA Ploidy Pattern, and Clinicopathologic Prognostic Factors in Invasive Ductal Carcinoma of the Breast

In this study of 64 cases of breast cancer with a clinical follow-up period of more than 5 years, several prognostic factors were evaluated. The purpose of this study was to determine whether any one parameter or group of parameters serves as adequate predictors of tumor behavior and patient's prognosis. Several prognostic factors included clinicopathological variables (patient's age, histologic grade, status of lymph node (LN) metastasis, and tumor size), expression of estrogen receptor (ER), progesterone receptor (PR), p53, bcl-2 and CD44 by immunohistochemistry, and DNA ploidy pattern. The results showed that the expression of ER and PR had a significant inverse correlation with the histologic grade (ER, p=0.05; PR, p<0.05). The expression of p53 protein showed a significant relationship with high histologic grade of tumor (p<0.05). The expression of bcl-2 protein was preferably seen in low histologic grade of tumor (p<0.05) and significantly associated with ER positive or PR positive tumors (ER, p<0.05; PR, p<0.05). This results suggest that bcl-2 protein might play significant roles in ER and PR. The CD44 expression showed a significant relationship with tumor size (p<0.05). The large size and aneuploidy pattern of tumor had a tendency to be associated with shorter patient survival. Cox's multivariate analysis showed that overall survival was affected by LN metastasis because of the shorter survival in patients with LN metastasis. In conclusion, tumor size, DNA ploidy pattern, and LN metastasis were themselves significant predictors of breast cancer survival rate.