In esophageal, pancreatic, and colorectal adenocarcinoma cell lines, activation of ATP at the micromolar range or its direct receptor subtype agonist on P2Y1 and P2Y2 receptors promoted S-phase arrest of the cell cycle, accompanied by a variable increase in apoptotic cell number [48,49]. The gene discussed is P2RY1; the disease is colorectal adenocarcinoma.