BRCA1 and breast cancer: The higher incidence of BC among Malaysian women under 40, compared to that in the U.S., is attributed to genetic predispositions (e.g., higher BRCA1/2 mutation rates), aggressive tumour subtypes (e.g., triple-negative BC), and lifestyle factors (e.g., diet, delayed childbirth, obesity), compounded by late-stage diagnoses linked to cultural healthcare practices [5].