CYP2A6 and neoplasm: Conversely, hepatic periportal markers (e.g., ALDOB, HAL, ASS1) and a subset of CYP-related proteins (e.g., CYP2A6, CYP2A7, CYP2B6) were either absent or downregulated in the tumor region (Supplementary Fig. 2b, c, h).