However, the EGFR T790M mutation, acquired RTK MET gene amplification and PIK3CA mutations, share the same effect of reestablishing the downstream PI3K/AKT/mTOR pathway in the presence of the anti-EGFR inhibitors, ultimately converting a TKI-sensitive tumor into a TKI-resistant tumor (27). The gene discussed is PIK3CA; the disease is neoplasm.