Clinical significance of bcl-2 gene expression in human breast cancer tissues

The expression of estrogen receptor (ER) and bcl-2(Bcl-2), an apoptosis protective oncogene, in normal andcancerous breast duct epithelia was immunohistochemically examined infresh frozen tumor tissues from 142 Japanese breastcancer patients. The clinico-pathological characteristics and the diseasefree survival of the patients were analyzed. Theexpression of both the proteins was also observedin intraductal components of breast cancer. Although lessthan 1% of normal duct epithelia expressed ER,Bcl-2 was diffusely expressed. The expression of boththese proteins in breast cancer significantly correlated witheach other. Their expression significantly correlated negatively withtumor size but not with lymph node status.The papillo-tubular sub-type of invasive ductal carcinoma expressedBcl-2 significantly more frequently than the solid-tubular sub-type.Patients with Bcl-2 expressing tumors survived without recurrencesignificantly more than those with tumors exhibiting reducedexpression. Papillary-cribriform type intraductal componentsexpressed both those proteins more often than the solid-comedo type.