MTHFR c.*177C>G (rs1801133), TS c.*450_*455del (rs11280056) and X-ray repair cross complementing 1 (XRCC1) (DNA repair protein) c.*310A>C (rs25487) mutated alleles have been associated with shorter survival in patients with myelodysplastic syndromes treated with azacitidine versus patients who only received supportive care [102]. This evidence concerns the gene XRCC1 and myelodysplastic syndrome.