PIK3CA and breast cancer: Notable findings in the mutational landscape include the mutually exclusive presence of GATA3 and TP53/PIK3CA pathogenic variants, higher levels of intratumoral heterogeneity, and genomic instability in breast cancer among Nigerian women, as well as the discovery of a unique breast cancer subtype defined by early clonal pathogenic variants in GATA3 and a younger age at diagnosis (17).