CYP1A1 and skin squamous cell carcinoma: This study aimed to evaluate the role of AHR and its downstream gene CYP1A1 in cSCC pathogenesis by examining its immunohistochemical expression in skin biopsies of normal controls and actinic keratosis (AK), Bowen disease (BD) and cutaneous squamous cell carcinoma (cSCC) patients and correlating their expression levels with the cell proliferation markers EGFR and Ki-67.