TET2 and cancer: Indeed, a growing number of studies have reported that vitamin C treatment rescued altered 5hmC levels in TET2-mutated cancers, directly reducing tumorigenic potential of cancer cells (17, 18), rendering malignant cells more sensitive to standard anticancer agents (19, 20) or by inducing an innate immune response through up-regulation of human endogenous retroviruses (HERVs) (21, 22).