CYP2B6 and lung carcinoma: CYP2B6 metabolically activates tobacco-specific nitrosamines, including the procarcinogen 4-(methylnitrosamino)-1-(-3-pyridyl)-1-butanone (NNK), while genetic variations in CYP2B6 have been suggested as a lung cancer risk factor in smokers (Wassenaar et al. 2013).