CYP2A6 and lung cancer: In a study mimicking the early stages of lung cancer development in rats under chronic NNK exposure, Kalscheuer et al., observed that the expression of several miRNAs, such as miR-101, miR-126*, miR-199 and miR-34, was decreased, while the expression of CYP2A3 was increased in the early stage of tumorigenesis, and reporter assays showed CYP2A3 is a direct target of miR-126* [13].