当前对肿瘤病因的认识,在两大学派(病毒学派及化学致癌学派)之间仍存在很大的分歧,但对肿瘤形成过程的看法却大体一致:肿瘤形成是个多步骤的过程,目前至少已有两个主要阶段,即激发阶段(Initiation)及促癌阶段(Promotion)已成公论,故不妨把这一理论称为实验性肿瘤研究中的两阶段理论。实验性肿瘤的研究是从皮肤开始,两阶段理论也是从研究皮肤肿瘤过程中总结出来的。由于篇幅有限,这里不作历史的回溯,但应指出的是,不但在皮肤而且在肝、膀胱、大肠等 At present, there is still a great deal of disagreement between the two schools (viral school and chemical carcinogenic school) on the understanding of the causes of tumors. However, the views on the process of tumor formation are generally consistent: Tumor formation is a multi-step process and has at least been There are two main stages, namely the initiation and the promotion of cancer, so it may be called a two-stage theory in experimental tumor research. The study of experimental tumors started from the skin, and the two-stage theory was also summarized from the study of skin tumors. Due to limited space, there is no historical retrospection here, but it should be pointed out that not only in the skin but also in the liver, bladder, large intestine, etc.