PTGS1 and diabetes mellitus: The four allelic variants of genes PTGS1, PLA2G2A, PPARG, and IL8 might favor inflammatory processes, whereas the MTHFR allelic variant could induce a DNA hypomethylation altering the expression of the putative tumor suppressor gene PPARG. Two recent studies on diabetes and cardiovascular diseases have suggested a common pathobiological mechanism between the inflammation process and genotype TT of MTHFR c.665C>T (aka C677T), i.e., a genotype inducing a lower MTHFR activity like genotype MTHFR c.1286CC [57,58].