Gery et al [5] demonstrated that PER1 was down-regulated in prostate and colon cancers and played a pro-apoptotic and cancer-suppressive role, while Sato et al [20] showed that PER1 was up-regulated in pancreatic and liver cancers and exerted an anti-apoptotic and cancer-promotive effect. The gene discussed is PER1; the disease is malignant colon neoplasm.