MAP3K1 and cancer: The luminal A subtype harbored a considerable number of mutated genes, with the most frequent being PI3KCA (about 45%), followed by MAP3K1, GATA3, TP53, CDH1, and MAP2K4. Approximately 12% of these tumors contained inactivating mutations in MAP3K1 and MAP2K4. Luminal B cancers, although, similar to luminal A cancers, exhibited a diversity of significantly mutated genes, with PI3KCA and TP53 (29% of each) being the most frequent [46].