PTEN and colonic neoplasm: Proximal colon tumors showed higher mutation frequencies than distal tumors on TGFBR2 (30.0% vs 2.8%, P < 0.001), ATM (20.0% vs 2.8%, P = 0.020), BLM (25.0% vs 2.8%, P = 0.005), and PTEN (15.0% vs 1.4%, P = 0.032) genes.