All are risk factors of squamous cell carcinoma except
Ultraviolet radiation, chronic inflammation, and chemical carcinogens (arsenicals, tar) and infection with HPV 5 and 16.There is also evidence that current and previous tobacco use doubles the relative risk of SCC.Ref: Bailey and Love, 27e, page: 606
Ultraviolet radiation
Tar
Tobacco
HPV 18
General surgery