The protein expression level of SIRT6 in CSCC is higher than that in the precancerous lesion Actinic Keratosis (AK) and normal skin tissue, suggesting that SIRT6 may play an important role in the progression from normal skin tissue to precancerous lesions and further to Cutaneous Squamous Cell Carcinoma. The gene discussed is SIRT6; the disease is actinic keratosis.