目前在日本由于恶性癌症而死亡的人数仅次于脑溢血占第二位。对其原因大致有化学和病毒两种学说。化学物质引起癌症早在1700年即为人们所发现。当时英国的扫烟筒工人皮肤癌多,因而产生了“煤的成分与皮肤癌之间的因果关系”的议论。第二次世界大战后,以α萘胺、β萘胺、联苯胺为原料的英国染料工厂的工作人员比一般人的膀胱癌发病率高达数十倍,成为劳动卫生上的大问题。日本也发生了类似事件。在美国4- Currently, the number of deaths from cancer due to malignant cancer in Japan is second only to stroke. The reason is roughly chemical and viral two doctrines. Chemical substances cause cancer as early as 1700 people found. At the time, there were many cancers in the UK for sweepers, which led to the argument that “the causal relationship between the composition of coal and skin cancer”. After World War II, alpha naphthylamine, beta naphthylamine, benzidine as a raw material for the British dye factory workers than the average incidence of bladder cancer up to several times, as a major health problems. A similar incident happened in Japan. In the United States 4-