PIK3CA and breast cancer: LGASC is regularly positive for P63 and negative for ER, PR, and HER2, and shares the molecular pathophysiology, gene expression profile, and immunophenotype of “triple-negative” and complicated basal subtypes of breast cancer.[11] It was found that the most significant cancer-associated alterations in TNBC patients were TP53 mutations (74%), followed by PIK3CA (18%), KMT2C (7%), and PTEN mutations (6%).