sentences:  Mounting evidence suggests that the NPAS2 protein and other circadian genes are involved in tumorigenesis and tumor growth, possibly through their control of cancer-related biologic pathways.A missense polymorphism in NPAS2 (Ala394Thr) has been shown to be associated with risk of human tumors including breast cancer.These findings provide evidence suggesting a possible role for the circadian "Npas2" gene in cancer prognosis.