**1. Introduction**

The Breast cancer has become great concern for global health scenario and health providers [1]. The incidence of it has surpassed the cervical cancers in Indian female [2]. The world over laboratory physicians across the world are engaged in assessing new and novel prognostic and predictive markers that would bring about best possible outcome at breast cancer treatment. The modern day practice of onco-pathology revolves more around predictive prognostic markers that would enable the appropriate adjuvant therapies and management of cancer. The challenges in breast cancer management is to predict its prognostic outcome, benefits of adjuvant therapy, surgical management and immunotherapy.The another challenge in breast cancer treatment is to understand molecular defect and thereby assessment of prognosis, and corrective therapies that would involute the primary tumour as well as metastasis [1, 2].

The conventional pathological prognostic factors in breast cancers which were until relied heavily were lymph node status, tumour size, tumour stage, tumour grade, Nottingham prognostic index and many others [2, 3].

With advent in understanding of pathogenesis of breast cancer many cell surface molecules, cytoplasmic signalling pathways, the nuclear transcriptional activities and many others have come under scanner which relates with breast cancer prognosis and treatment outcomes, especially with chemotherapeutic interventions and monoclonal antibody therapies [4].

Among many such families of the genes, Bcl-2 has been studied extensively for its commonality at participation in the pathogenesis of solid tumours especially the cancers of breast, prostate, lung, colo-rectum and ovaries [5, 6].

**Figure 1.** *Flowchart – Evasion of cell death.*

*Bcl-2 Immunoexpression in Invasive Ductal Carcinoma and Its Evaluative Correlation… DOI: http://dx.doi.org/10.5772/intechopen.109297*

Bcl-2 is an anti-apoptotic protein normally expressed in mammary tissue and is up-regulated by oestrogen in breast cancer through direct consequence of transcriptional induction.

Bcl-2 is a principle member of anti-apoptotic proteins along with Bcl-XL and MCL-1. The release of pro-apoptotic proteins in the cells such as cytochrome-c is through the integrity of the mitochondrial outer membrane. This is tightly controlled by Bcl-2 family of proteins. Bcl-2 is overexpressed due to chromosomal translocations and certain mutational changes. Bcl-2 protein also resides in the cytosol and ER membranes. Impermeability by Bcl2 protein prevents the leakage of cytochrome and thereby limits the process of apoptosis. The one way, Bcl-2 genes and their proteins plays an important role in intrinsic pathway of apoptosis [7]. Therefore Bcl-2 genes is one of the genes which is at the centre stage in the pathogenesis of the breast cancer (**Figure 1**).

A few studies in published literature did correlation between Bcl-2 immunoexpression and clinico-pathological variables, disease free survival, prognostic factors, Nottingham prognostic index, TNM stage and treatment outcome [8, 9]. A few studies have proposed that Bcl-2 expression be considered as a molecular subtype of invasive ductal carcinoma because of clinical implications [10, 11].

The search for publications over this topic originating in India was found to be marginal which correlated clinicopathological variables, molecular subtypes of breast cancer and BR-grades [12, 13].

The Bcl-2 expression as published in the western literature have shown its predictive utility and therefore its inclusion in the reporting of histopathology is considered as an essential component [14, 15]. Detecting Bcl-2 immunoexpression in the tumour cell therefore create a frame for appropriate treatment and management of invasive ductal carcinoma.

### **2. Methodology**

The chapter includes the observation on Bcl-2 immunoexpression in invasive ductal carcinoma and its evaluative correlation with BR grade, TNM stage and molecular subtypes as gathered from published literature. Most of the published literature detected Bcl-2 immunoexpression by immunohistochemistry performed on paraffin sections of breast lumps diagnosed as invasive ductal carcinoma.

The authors of the present chapter adopted the methodology for performing the immunohistochemistry in demonstration of Bcl-2, ER, PR and Her 2 on paraffin tissue section as described in the previous studies [6].

The present study included 50 cases whose complete demographic details, clinical examination of the breast lumps, relevant clinical examination, mastectomy details, gross examination finding of specimen, subsequent tissue diagnosis, BR grading, and TNM staging was carried out. The work included only those cases of invasive ductal carcinoma whose complete clinical records and follow up of at least 6 months were available.

The studies whose results are a part of the present chapter performed immunohistochemistry by standard methods meant for it, in detection of ER, PR, Her 2 nu and Bcl-2. The results and interpretation of positivity and score of immunohistochemistry for Bcl-2 and ER, PR, Her 2 were aligned.

The statistical tests used for comparison of the results contained in the present chapter were similar as performed by the authors of other studies.
