Although the main biological effects on cancers are attributed to its role in the redox cycle and arylating nucleophilic substrates, Vit K3 has been identified as a specific inhibitor of Siah2 that inhibits both arms of the Siah2 downstream signaling network, the Ras/MAPK pathway and the hypoxic response pathway independent of reactive oxygen species. This evidence concerns the gene SIAH2 and cancer.