CLOCK and neoplasm: For instance, it is known that the CLOCK gene product activity can affect both estrogen [21] and androgen pathways [22], which is concordant with the relationship between circadian pathway perturbation and the risk of hormone-driven malignancies such as breast and prostate cancer, respectively; however, the association with lung carcinoma remains less intuitive and warrants further investigation on the cascade of molecular events underlying the link between the biological clock and this type of tumour.