role in cancer development (a disease of unregulated cell proliferation), our results suggest that some of the same biological mechanisms underlie both smoking and cancer, as first conjectured by Fisher47: “[…] cigarette smoking and lung cancer, though not mutually causative, are both influenced by a common cause, in this case the individual genotype”. While the mediation study by VanderWeele et al. 48 demonstrated that variants at the 15q25 locus have a direct effect on both smoking and lung cancer, it will be of interest to determine whether their conclusion generalizes at the pathway level as suggested by the present results. If that is the case, the novel cancer therapies targeting the cell-cycle regulators 49 might yield clues of particular importance for the development of efficient smoking cessation therapy.
