Therefore, we sought to assess the epigenetic regulation of CYP1A1 in two human carcinoma cell lines derived from distinctly different epithelial cell types, HepG2 hepatocarcinoma cells and HeLa cervical carcinoma cells, which showed significantly different levels of CYP1A1 induction after PCB 126 challenge. Here, CYP1A1 is linked to carcinoma.