p53 and Rb alterations in primary breast carcinoma: Correlation with hormone receptor expression and lymph node metastases

Expression of Rb and mutant p53 nuclear phosphoproteins was analyzed immunohistochemically in 69 breast cancer patients. Results were correlated with hormone receptor (ER and PR) and lymph node (LN) status. There was a significant association between the immunohistochemical evidence of p53 and/or Rb alterations and loss of hormone receptor expression. Mutations in p53 and/or low level Rb expression were not associated with the presence of axillary lymph node metastases. However, in patients with hormone receptor positive tumors, there was statistically significant correlation between altered expression of p53 and/or Rb and the presence of LN metastases. These results indicate that: (i) loss of steroid hormone receptor expression (and thus loss of hormonal growth control) is accompanied by somatic inactivation of the p53 or Rb tumor suppressor genes; and (ii) in tumors that remain under hormonal growth regulation inactivation of p53 and/or Rb may play a role in tumor progression.