H19 and rectal neoplasm: Analyses by tumor localization revealed that H19 rs2839698 and PTCSC3 rs944289 were more frequent in colon than in rectal tumors (p = 0.017 and p = 0.035) and were associated with a reduced risk of rectal tumors (OR = 0.18 and OR = 0.20), suggesting that these variants may influence tumor site rather than overall susceptibility.