Molecular Subtypes by Immunohistochemical for Iraqi Women with Breast Cancer

Abstract

Breast cancer is a complex disease encompassing multiple tumor entities, each characterized by distinct morphology, behavior and clinical implications. Hormone receptor status and HER2 status are of critical interest in determining the prognosis of breast cancer patients. Their status is routinely assessed by immunohistochemistry (IHC). The aim of this study is to clarify the differences in the expression of the established prognostic and predictive markers ER, PR and HER2 with breast cancer by IHC. This study was conducted at AL-SADER Hospital in AL-Najaf and Medical city in Baghdad, Iraq, from July 2018 to April 2019. It included fresh tissue of 48 patient women with breast cancer. Immunohistochemical staining with antibodies for Estrogen Receptor (ER), Progesterone Receptor (PR) and Human Epidermal Growth factor 2 (Her 2) was performed and then breast cancers were classified into four molecular subtypes: Luminal A (ER/PR +, HER2-), Luminal B (ER/PR +, HER2+), Triple Negative Breast cancer (Basal like) (ER/PR -, HER2-) and HER 2 (ER/PR -, HER2+). Clinical parameters were compared using chi-square test. In the current study ER receptors was 72.91% (35/48), PR positive receptors 56.25 % (27/48) and that 11 out of 48 malignant cases were represent as 22.91 % were positive for her2/neu expression. Corresponding for the hormones statues, the molecular subtype was: Luminal A group 56.25% (27/48), Luminal B subtype which was 16.66% (8/48), then a group with triple negative ( ER-, PR- and HER2- ) was 18.75% (9/48) cases that represent Basal like group, while the other groups appeared least frequency as a following: HER +, ER- and PR- were (4) cases only which were referred to HER2 subtype group. There is certain variation among the molecular subtype of breast cancer with prevalence of certain types among different regional population.