In particular, it was reported that luteolin could be metabolized into 6 hydroxyluteolin by recombinant CYP1B1, but not by CYP1A1 and CYP1A2, and that hydroxylation of luteolin at the 6 position of the A ring is crucial for the antiproliferative activity in breast cancer cells. This evidence concerns the gene CYP1A1 and breast cancer.