GSTM2 and obesity due to melanocortin 4 receptor deficiency: In male and female rats with obesity, we found an overexpression of the oncogenes SURVIVIN/BIRC5 and MYC, which are involved in cell proliferation and the inhibition of apoptosis [33,34]; a decrease in the transcriptional levels of the GSTM2, SIRT1 and SIRT6 genes, which are involved in protection against cellular oxidative stress and in the repair of DNA damage [35,36]; and a decrease in the tumor suppressors TGFB1, TP53 and PTEN, which are involved in the regulation of cell growth [37,38,39].