Immunohistochemical-Based Molecular Subtypes of Female Breast Cancer: A Retrospective Cross-Sectional Study at Cheikh Khalifa Hospital in Casablanca, Morocco

Abstract

Introduction: Breast cancer is a major public health concern worldwide and the most prevalent form of cancer in Morocco. This study aimed to describe the histological and immunohistochemical profiles of breast cancer in women admitted to Cheikh Khalifa Hospital in Casablanca, Morocco.

Methods: This is a retrospective cross-sectional study. All histologically confirmed female breast cancer cases diagnosed between January 2017 and May 2021 at the Cheikh Khalifa University Hospital were included in the study. Data were collected from patient electronic medical records. Using an electronic sheet, information was collected about the socio-demographic characteristics of the patients, clinical features, histopathology, molecular characteristics, treatment received, and progression.

Results: Invasive carcinoma of no special type was the most common type of cancer accounting for 90.7% of all cases. The majority of the tumors (56.1%) were grade II tumors. About 42.1% of tumors were lymph node-positive and only 13.4% developed distant metastasis. Immunohistochemical data revealed that 57.9% of the tumors in this study were hormone receptor-positive (ER+ and PR+), 74.4% were estrogen receptor-positive (ER+), 58.5% were progesterone receptor positive (PR+), and 18.9% were HER2 positive (HER2+). The most common molecular subtype was Luminal A-like (43.9%). A statistically significant difference was found in histological grades across the four molecular subtypes (P < 0.001).

Conclusions: Our findings should be used to guide breast cancer management policies in Morocco. Larger cohort studies are needed to determine the specificity of the breast cancer profile in Morocco as well as the epidemiological risk factors specific to every subtype.

Keywords: Morocco; breast cancer; cancer epidemiology; immunohistochemistry; molecular subtypes.