MCL1 and head and neck squamous cell carcinoma: Since the modification effect of NOXA and MCL1 variants on SCCHN risk associated with HPV16 seropositivity was particularly evident for oropharyngeal cancers, we further evaluated the effect modification of the variants on risk of oropharygeal cancer associated with HPV16 seropositivity stratified by smoking/drinking status and age (Table 4, 5, 6).