Overexpression of c-erbB-2 oncoprotein and associated pathobiological factors in invasive primary breast cancer.

Breast cancer tissues from 271 cases were analyzed immunologically for c-erbB-2 oncoprotein (HER-2/neu), epidermal growth factor receptor (EGF-R) and estrogen receptor (ER). Overexpression of both c-erbB-2 oncoprotein and EGF-R showed an inverse association with ER and a direct association with metastatic involvement of lymph node and high histological grade. The frequency of c-erbB-2 and EGF-R overexpression was significantly higher among postmenopausal cases in comparison with premenopausal cases. Further, only in postmenopausal patients, c-erbB-2 oncoprotein (chi2 = 6.4, P < 0.05) and EGF-R (chi2 = 6.4, p < 0.05) as well as their concomitant expression (chi2 = 11.5, p < 0.01) revealed a statistically significant association with ER.