The Association Between Clinicopathological Features and Molecular Markers in Bahraini Women With Breast Cancer.

Introduction: Breast cancer (BC) is a heterogenous disease and a major public health burden in Bahrain. Based on hormone receptor status (ER, PR, and HER2), BC can be divided into four molecular subtypes: Luminal A, Luminal B, HER2+, and Triple negative, each of which display distinct clinical behaviour.

Patients And Methods: This retrospective study included 216 patients diagnosed with BC between November 2017 and May 2019 at the Bahrain oncology centre. The clinicopathological characteristics (age, size of tumour, grade, lymph node involvement, metastasis) were examined, in addition to immunohistochemical markers (ER, PR, and HER2), and BRCA 1 and 2 status (when indicated). SPSS was used to evaluate the correlation between the molecular subtypes and different clinicopathological features.

Results: BC in Bahraini women was relatively of large size (68.5% larger than 20mm), with frequent metastasis to the lymph nodes (57.4%). The mean age at diagnosis was 51.8 years ±11.5, with invasive ductal carcinoma (IDC) being the most common histological type (90.3%). The most common molecular subtype was Luminal A (60.2%), followed respectively by luminal B (19%), triple negative (13.4%) and HER-2 (7.4%).

Discussion: Significant differences were found between the subtypes regarding grade (p=0.001) and BRCA mutation status (0.001). Triple negative subtype was associated with highly-aggressive behaviour compared to the other subtypes. It presented at younger age, with high grade, large tumor size, and predominance to distant metastasis. It was also linked with positive BRCA mutations.

Conclusion: A significant proportion of Bahraini females with BC present with aggressive features (i.e. younger age, poorly differentiated tumors, and lymph node involvement). Expectedly this was associated with underlying aggressive molecular subtypes (namely TNBC). The aggressive properties of such molecular subtype mandate further molecular testing to identify more accurate prognostic and predictive targets for effective treatment and risk reduction strategies.