GSTM1 and breast cancer: DNA hypermethylation of corresponding CpG sites in certain tumor-promoting genes such as urokinase-type plasminogen activator (PLAU), ADAM metallopeptidase domain 8 (ADAM8), tumor necrosis factor (ligand) superfamily member 12 (TNSF12), and genes related to detoxification; glutathione S-transferase mu 1 (GSTM1) and mitochondrial metabolism malic enzyme 3 (ME3) genes correlate with receptor tyrosine-protein kinase ERBB-2 amplification (HER2)/estrogen receptor (ER)/PR status in primary BC tumors (85).