**Abstract**

Invasive Ductal carcinoma is the most common histological type of breast cancer. It constitutes about 80 percent of all breast cancer diagnoses. The molecular pathogenesis of breast cancer involves multiple gene types. Bcl-2 is one of them. Bcl-2, is an antiapoptotic protein which is up regulated by oestrogen in breast cancer patients. The immunoexpression of Bcl-2 detection is being carried out by immunohistochemical methods as described in many published studies. Bcl-2 as is known acts through transcriptional induction in pathogenesis of breast cancer. The present chapter describes the role of Bcl-2 in pathogenesis, significance and its relationship with BR Grade and TNM stage. The present chapter specifically describes its observation of Bcl-2 immunoexpression and relationship with molecular subtypes of breast carcinoma.

**Keywords:** Bcl-2, breast cancer, BR grade, TNM stage, molecular sub-types
