p53 protein overexpression in infiltrating ductal carcinoma of female breast and its association with lymph node metastasis

Traditionally, prognosis in carcinoma of the breast is evaluated based on size and differentiation of the tumor and status of lymph node metastasis. In addition to these established markers, in this molecular age other parameters such as overexpression of p53, c-erbB-2 and c-myc proteins are increasingly used to assess the prognosis. At present, the prognostic value of the molecular markers, at best, is controversial and conflicting. In this study, we examined 67 infiltrating ductal carcinomas of female breast with and without lymph node metastasis for p53 protein overexpression by immonohistochemistry on formalin-fixed, paraffin-embedded tissue sections to ascertain if p53 positive tumors have greater metastatic potential than p53 negative tumors. In addition, p53 overexpression was also correlated with tumor size, grade, expression of estrogen and progesterone receptors, and age of the patient to clarify the issue of relevance of p53 overexpression in prognostication. p53 overexpression was observed in 39% of tumors and showed strong correlation only with the histological grade of the tumor. The incidence of p53 overexpression in grade 1, grade 2 and grade 3 tumors was 0%, 33% and 58% respectively. Lymph node metastasis was less frequent in tumors that overexpressed p53 protein. Twenty-seven percent of primary tumors with lymph node metastasis showed p53 protein overexpression, in contrast to 44% of tumors without metastasis. No correlation was observed between p53 overexpression and all the other parameters evaluated except progesterone receptor negative status. These results suggest that p53 overexpression is not an independent prognostic indicator and should not be used to predict lymph node metastasis or aggressive behavior of the tumor.