The EGFR-c-Raf-MEK and PTEN-mTOR-Akt signaling pathways are closely associated with cancer cell properties, and we therefore suggest that the modulation of EGFR-c-Raf-MEK and PTEN-mTOR-Akt by RPE could be the underlying mechanism responsible for RPE’s anti-cancer activity. The gene discussed is PTEN; the disease is cancer.