PIK3CA and breast cancer: For example, disruption of the interaction between laminin 332 and α6β4- or α3β1-integrins, and thereby the PI3K/AKT, MAPK/ERK1/2 and focal adhesion kinase (FAK) signaling and cell adhesion, sensitizes HER2+ BC cells to trastuzumab and lapatinib treatments (52).