Exposure to weak AhR ligands such as hexachlorobenzene and chlorpyrifos also reduce LINE-1 methylation levels and induce LINE-1 reactivation, i.e., increased mRNA expression, in both MDA-MB-231 breast cancer cells and non-tumoral breast epithelial cells (i.e., NMuMG cell line) [165]. The gene discussed is AHR; the disease is breast cancer.