CHRNA5 and nasopharyngeal carcinoma: In addition, the combined variant genotypes (ins/del+del/del), in conjunction with cigarettes smoking, increased NPC risk, thus indicating that the CHRNA5 rs3841324 variant not only could be a risk factor and a novel biomarker for prediction of smoking related NPC risk, but also might be involved in the etiology of cigarette smoking-mediated cancer.