To explicitly explore the potential contribution of altered nitrosamine pharmacology to lung cancer risk among smokers, we have extended our investigation of gene variants to CYP2B6. CYP2B6, like CYP2A6, is expressed in the lung in addition to the liver [4,5] and metabolically activates TSNAs to DNA-reactive products [2,6]. Here, CYP2A6 is linked to lung cancer.