Study on Intratumoral Heterogeneity of Expression of Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor 2 in Carcinoma Breast

The aim of this study was to study intratumoral heterogeneity in the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) between two different cores/blocks of core needle biopsy (CNB), two different blocks of the same lesion in resection specimen (RS), and in between the CNB and RS. This is a prospective observational study of all the cases of breast carcinoma received in the department of histopathology for 2 years. All the patients with breast carcinoma diagnosed by CNB and RS were analyzed by three pathologists independently by immunohistochemistry. Of the 75 cases, 74 were females and 1 male with a peak incidence of 60–70 years. Invasive breast carcinoma of no special type (97%) was the most common, followed by invasive lobular carcinoma (3%). Grade III tumors (44%) were more common, followed by Grade II (39%) and Grade I (17%). ER and PR showed a concordance rate of 96% (P < 0.05), whereas the HER2 showed a concordance rate of 93% (P < 0.05%). The concordance of ER decreased with increasing tumor size and grade, while PR and HER2 showed variable concordance with tumor size and grade. The concordance rate of ER and PR (96%) was higher than (93%) HER2. In most cases, biomarker expression in core biopsy and single tumor block was reflective of breast carcinoma as a whole. However, because of the heterogeneous expression of biomarkers, we recommend testing tumors with negative biomarker expression on CNB, again on the RS.