PIK3CA and cancer: Studies have shown that downregulation of miR-93 in NSCLC inhibits cell proliferation and apoptosis.15 miRNA-223 has been shown to suppress cancer cells by targeting the EGFR/AKT2 pathway in NSCLC.16 Some studies have demonstrated that the PI3K/AKT/mTOR pathway is an important player in EGFR-TKI resistance.17,18 Loss of the PTEN gene, the protein product of which functions downstream of the PI3K/AKT/mTOR pathway, has been shown to play an important role in erlotinib and gefitinib resistance in EGFR-mutated NSCLC.19