你这问题问的，真大，估计资深癌症专家也没法回答你。有遗传， 也有环境和各种因素，比如年老，抽烟，各种不同的癌症有不同易感因素，乳腺癌有激素的原因，胃癌什么的有它们自己的高发原因。建议你去GOOGLE一下

lz去读本肿瘤学的书就明白了

有种说法是每个人都有癌细胞 你身体状况好 它就不发作

回复 [url=http://forums.huaren.us/showtopic.aspx?topicid=2068376&postid=72809151#72809151]2楼ll4321的帖子[/url] 好吧，也感觉问题问大了。

据我观察 知道的所有癌症患者都每天喝水

还呼吸空气 哈哈哈

大部分不上华人

A book explained it pretty well and also written in simple non-scientific language. Cancer: Empire of all maladies. PBS made this into a documentary movie. Very well. The documentary is more update with the immunotherapy which was absent in book which was published before the application of immunotherapy.