肿瘤(tumor)是机体在各种致癌因素作用下,局部组织的某一个细胞在基因水平上失去了对其生长的正常调控,导致其克隆性的异常增生而形成的异常病变。医学中一般将肿瘤分为良性和恶性两大类,而肿瘤的发生发展过程就是机体正常的细胞在各种致癌因素的协同作用下引起DNA的损害, Tumor (tumor) is a body under the action of various carcinogenic factors, a local tissue of a cell at the gene level lost its normal regulation of growth, leading to its clonal abnormal proliferation and the formation of abnormal lesions. In medicine, tumors are generally divided into benign and malignant two categories, and the occurrence and development of tumors is the body’s normal cells in a variety of carcinogenic factors under the synergistic effect of DNA damage,