Hormone receptor (ER, PR, HER2/neu) status and proliferation index marker (Ki-67) in breast cancers: Their onco-pathological correlation, shortcomings and future trends

Abstract

Estrogen receptor (ER) and progesterone receptor (PR) are hormone receptors found on breast cells that pick up hormone signals resulting in cell growth. Similarly, positive human epidermal growth factor receptor-2 (HER2/neu) status of the breast carcinoma means that HER2/neu gene is making too many HER2/neu proteins, which acts as receptors on the cell surface and helps the cells to grow and divide. Hormone receptor studies such as ER, PR, and HER2/neu are routinely done in breast carcinoma. It not only helps in the prognosis of the tumor but also helps in deciding its treatment. The goal of doing this receptor status is to provide right treatment to the right patient. This hormone receptor status is graded using Allred scoring and grading system. Depending on the hormone status, breast carcinomas can be divided into a number of different categories ranging from triple positive through triple negative. Another marker of proliferation (Ki-67) is also being used which is a proliferation index marker. This scoring system has its own limitation and shortcomings, which depends on a lot of pre- and post-analytical factors. Certain new techniques such as genomic assays, PAM50, and HALO screening test are being used nowadays for breast cancer detection.