CYP1B1 and breast cancer: In the case of breast cancer cells, the CYP1A1 protein level was slightly reduced by 3,4,2′-trimethoxy (3MS) and 3,4,2′,4′-tetramethoxy (4MS), and the CYP1B1 expression was decreased as a result of the treatment with 4MS, but only at the transcript level in MDA-MB-231 cells [80,81].