SELENOP and cancer: In this regard, a variety of selenoproteins have been demonstrated to influence the development of cancer in different directions: global SELENOP haploinsufficiency augments tumorigenesis and mediates oxidative damage in the intestine [42]; Thioredoxin reductase 1 plays a role in cancer promotion [43,44,45]; SELENOF (Sep15) plays a stimulatory role in colon cancer [46,47].