TET-family dioxygenases and the TET activator Vitamin C in immune responses and cancer.

Vitamin C serves as a cofactor for Fe (II) and 2-oxoglutarate (2OG)-dependent dioxygenases including TET family enzymes, which catalyze the oxidation of 5-methylcytosine into 5-hydroxymethylcytosine and further oxidized methylcytosines. Loss-of-function mutations in epigenetic regulators such as TET genes are prevalent in hematopoietic malignancies. Vitamin C deficiency is frequently observed in cancer patients. In this review, we discuss the role of vitamin C and TET proteins in cancer, with a focus on haematopoietic malignancies, T regulatory cells and other immune-system cells.