PIK3CA and breast cancer: Canonical pathways selectively upregulated in Her2+ compared to ER+ and triple-negative BC samples involve the actin cytoskeleton and extracellular matrix, integrins, actin-based motility through Rho and Cdc42, integrin-linked kinase (ILK), PI3K/AKT, phospholipase C, protein kinase A, FAK, serine/threonine p21-activated kinase PAK1 (PAK1), and several other pathways associated with motility, cell structure, guidance, and endocytosis [360].