Immunohistochemical analysis of estrogen and progesterone receptor and neu expression in breast carcinoma

To elucidate the frequency and biological significance of the expression of estrogen receptor (ER), progesterone receptor (PR), and neu oncogene in breast carcinoma, ER, PR and neu proteins were examined by immunohistochemical assay in 74 Taiwanese patients with breast carcinoma. In total, 56.8% and 48.7% of breast carcinoma were positive for ER and PR, respectively. In 91.9% of cases, the patients were either positive (48.7%) or negative (43.2%) for both ER and PR. Well differentiated carcinoma had higher frequencies of ER- (p < 0.02) and PR-positivities (p < 0.01). The ER and PR status did not correlate with tumor size, stromal lymphoid infiltration or axillary node status. The neu oncoprotein was expressed in 25.7% of breast carcinomas, but did not correlate with ER and PR status, tumor size, tumor grade, lymphoid infiltration, or axillary node status.