Immunogenomic Characterization of Triple-Negative Breast Cancer in a Moroccan Cohort and Its Prognostic Implication

Background: In North Africa, triple-negative breast cancer (TNBC) is a highly prevalent, aggressive, and diverse disease with unique clinical features. In this population, the prognostic significance of immune infiltration and genomic changes is still not fully understood. In order to investigate their relationships with relapse-free survival, this study sought to provide an integrated analysis of the tumor immune microenvironment and BRCA1 and BRCA2 variant landscape in Moroccan TNBC patients. Methods: A retrospective cohort of Moroccan TNBC patients was evaluated using immunohistochemistry (IHC) to assess stromal tumor-infiltrating lymphocytes (TILs), programmed death-ligand 1 (PD-L1) expression, and immune cell subsets (CD3, CD4, CD20, and CD56). Targeted next-generation sequencing of BRCA1 and BRCA2 was performed on tumor tissue. Associations between immune biomarkers, genomic variants, and clinical outcomes were analyzed using appropriate statistical and bioinformatic approaches. Results: The cohort exhibited significant heterogeneity in immune infiltration and advanced disease at diagnosis. Higher stromal TIL levels were observed in patients without relapse, although this association did not reach statistical significance in the present cohort. BRCA1 and BRCA2 variants were frequently detected and showed heterogeneous immune profiles across tumors. Limited redundancy among immune markers was found in correlation analyses, suggesting that these markers may capture complementary aspects of the immune microenvironment. Conclusion: This integrated immunogenomic analysis suggests the potential prognostic relevance of the tumor immune microenvironment in Moroccan TNBC patients. The findings emphasize the value of multiparametric immune and genomic profiling for improved risk stratification and support further investigation of population-specific immunogenomic patterns in North African TNBC patients.