GSTM1 and pachyonychia congenita: Taking into consideration the involvement of oxidative stress in PC pathogenesis and recent advances in scientific understanding of the role of GSTP1*Ala114Val rs1138272 in carcinogenesis, we hypothesized that this SNP influences the risk of PC independently of, or in combination with, another GST polymorphisms such as GSTP1*IIe105Val rs1695 or GSTM1 and GSTT1 deletion polymorphisms.