Abstract:

Background: It is observed that seven percent of all the cases of breast cancer of whole world belong to our country. If our country is being considered then it has been found that more than twenty percent of all cancers affecting females is the breast cancer. The main concern regarding the management of breast carcinoma is the non homogenous characteristics of the breast tumour. Among the various classifications to reduce this non homogenecity in breast carcinoma the most accepted classifications has been based on the genetic characteristics of the tumours. In recent times there has been several studies has been conducted in other populations focussing on the immune histochemistry markers like Ki 67, cytokeratin 5/6, human epidermal growth factor receptor ( HER) and progesterone receptor (PR) in breast carcinoma for assessing molecular and histological subtypes of breast cancer.Aim: To evaluate molecular subtypes and histological subtypes of breast cancer based on immune histochemistry markers for assessing the behaviour and disease aggressiveness Methods and Materials: Immunohistochemistry was performed using four main markers ER, PR, HER2, and Ki67 to classify them into four molecular subtypes Luminal A, Luminal B, TNBC and HER2. An additional marker CK5/6 was used to further classify TNBC into Basal like and Non Basal like. The characteristics of two subtypes Basal like and non basal like TNBC were analyzed separately. These molecular subtypes and tumour histological subtypes were correlated with clinocopathological parameters viz. Age, menopausal status, laterality (right or left), tumour size, tumour grade, LVI, necrosis, stromal reaction, lymph node status, pathological T stage(pT), pathological N (pN) stage, Nottingham’s prognostic index (NPI).Results: In present study the age range of patients was between 28 to 80 years, with majority of patients in age group of 50 to 59 years. The mean age of presentation of histological subtypes was Infiltrating duct carcinoma, no special type (IDC-NST) – 53.56 years Infiltrating lobular carcinoma (ILC) – 54.08 years. Other histological subtypes – 57.07 years. In our study out of 278 patients, 105 were in premenopausal group and 172 were in postmenopausal group. Molecular subtypes was found to be more associated with aggressiveness of disease as compared to histological types. Conclusion:In comparison to histological subtypes, molecular subtypes can be a better tool for analysing the behaviour and disease aggressiveness of breast cancer, according to the findings of this study. We recommend that molecular classification be performed on all breast cancers and that it be used in conjunction with histological classification. It would be premature to dismiss histological classification at this time.

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