GSTP1 and type 2 diabetes mellitus: Unlike other diseases such as neoplasms [31, 32] in which GSTM1 and GSTT1 polymorphisms are extensively investigated, there are few studies that investigate the association between GSTM1, GSTT1, and GSTP1 gene variants and the presence of microvascular complications in T1DM and T2DM [33, 34].