PIK3CA and cancer: This study also identified Rheb mutations in patients with RCC leading to an increase in mTORC1 activity.93 The mutations, amplification, and overexpression of PIK3CA, KRAS, AKT, IGFR, and EGFR are more common in cancer, which are upstream molecular targets for mTOR complexes resulting in the activation of the mTOR signaling cascade in human malignancies.