GSTM1 and diabetes mellitus: Null variants occurring in theGSTT1 and GSTM1 genes are the most commonpolymorphisms in GST proteins, and their association with variouschronic-degenerative diseases such as hypertension, diabetes, asthma, and differenttypes of cancer including prostate, neck, colorectal, liver and leukemia has beenthoroughly studied in different populations (Songet al., 2012; Zhanget al., 2012; Lianget al., 2013; Liuet al., 2013; Eslamiand Sahebkar, 2014; Heet al., 2014; Raoet al., 2014; Masoodet al., 2015).