Role of immunohistochemical markers in breast cancer and their correlation with grade of tumour, our experience

Abstract

Breast cancer is a major concern and one of the leading causes of cancer related death worldwide. Breast cancer like many other types of cancer is a complex heterogeneous disease controlled by a multitude of genetic and epigenetic alterations.1. In Pakistani females, breast carcinoma occurs at a younger age group. Infiltrating ductal carcinoma is the most common type of tumour.2 Male breast carcinoma is an uncommon disease.3 Less than 1% of all breast carcinomas occur in men.4,5 The pathology is similar to that of female breast cancer, and infiltrating ductal cancer is the most common tumor type.6 During the past two decades the mortality rate has declined significantly, primarily due to the early use of adjuvant chemotherapy as well as detection of earlier stage tumours due to increased screening.7,8 Prognosis and management of breast cancer is influenced by the classical variables such as histological type and grade, tumour size, lymph node status, and status of hormonal receptors, Estrogen receptors (ER) and progesterone receptors (PR) of the tumour and more recently Her2Neu oncoprotein status.8,9 ER expression is undoubtedly the most important biomarker in breast cancer, because it provides the index for sensitivity to endocrine treatment. ER positive tumours (80% of breast cancer) use the steroid hormone estradiol as their main growth stimulus; ER is therefore direct target of endocrine therapies. PR expression is strongly dependent on the presence of ER. Tumours expressing PR but not ER are uncommon and represent <1 % of all breast cancer.10 The proto–oncogene(C–erb) has been localized to chromosome 17q and encodes a transmembrane tyrosine kinase growth factor receptor. The name for the Her2 Neu is derived from human epidermal growth factor receptor, as it features substantial homology with the epidermal growth factor receptor (EGFR).11,12 Amplification and/or overexpression of Her2/ Neu gene is routinely evaluated using immunohistochemistry and or/ fluorescence insitu hybridization (FISH) in all cases of invasive breast carcinoma. Her–2 Neu amplification occurs in about one quarter to one fifth of breast cancers.13 The purpose of this study was to analyze the immunohistochemical markers in invasive carcinoma of breast and to assess the relationship of hormonal receptor status and Her2 Neuoncoprotein over expression with tumour grade.