We observe that reduction of basal CYP1A1 expression leads to significant inhibition of cell proliferation through induction of apoptosis in prostate cancer cells, indicating CYP1A1 expression is critical for cell growth, and this is in concordance with Hruba et al. [6] who showed that enhanced CYP1A1 levels induced by benzo[a]pyrene displayed no effect on either apoptosis or cell cycle arrest in LNCaP cells. The gene discussed is CYP1A1; the disease is prostate cancer.