在临床实践中可以看到一些非常有意义的现象,某些病人的肿瘤可以自行消退,如神经母细胞的病人中,自行消退者可达2—18%。还有些病人可带瘤长期生存,如肺癌病人有的曾带病生存9年,甲状腺癌病人生存过30年。此外,体细胞也经常发生突变,但癌的发生也并不那么经常,这说明体 Some very significant phenomena can be seen in clinical practice. Some patients’ tumors can resolve on their own. For example, in patients with neuroblasts, spontaneous regression can reach 2-18%. Some patients may also have long-term survival with tumors. For example, some patients with lung cancer have survived for 9 years and thyroid cancer patients have survived for 30 years. In addition, somatic cells are often mutated, but the occurrence of cancer is also not so frequent, which shows that