化学致癌过程 4、先用PAHs处理小鼠皮肤，再用巴豆油处理，小鼠皮肤出现乳头状 瘤；如果将巴豆油撤去，乳头状瘤可以消退；相反，如果已豆油 继续刺激，乳头状瘤癌变为鳞状细胞癌。 Papillomas Initiator Initiated Promoter (first) cells (second) Promoter continued Promoter withdrawn Invasive squamous Initiated cell carcinoma cells