求翻译：癌症的产生原因是什么呢？国内外医学界已经证实，人类80%～90%以上的癌症与外部环境因素相关，也就是人类生活环境中的物理、化学和生物因素与癌症的发生密切相关。是什么意思？

Causes of cancer is it? Domestic and international medical community has confirmed human 80% to 90% of cancer and external environmental factors related to the human living environment is the physical, chemical and biological factors and cancer are closely related.

What is the reason for cancer? Domestic and foreign medical profession has confirmed that human 80 % ~ 90% of the cancer with external environmental factors, that is, human environment in which relevant physical, chemical and biological factors and cancer of the closely related.

What is cancer production reason? The domestic and foreign medical arenas already confirmed that, human 80%~90% above cancer and the external environment factor are related, also was in humanity living conditions physics, chemistry and the biotic factor and the cancer occurrence close correlation.

Causes of cancer, what do we mean? Medical profession has been shown at home and abroad, more than human 80%~90% cancer associated with external environmental factors, that is, human life and the physical, chemical and biological factors on the environment is closely related to cancer.

Causes of cancer, what do we mean? Medical profession has been shown at home and abroad, more than human 80%~90% cancer associated with external environmental factors, that is, human life and the physical, chemical and biological factors on the environment is closely related to cancer.