转移是指恶性细胞从原发性肿瘤播散至其它组织和器官,形成继发性肿瘤的过程。发生转移被认为是确定肿瘤性质的无可置疑的证据。转移常导致病人死亡,因此,如能控制转移,就能把恶性肿瘤的危险性降至如同良性肿瘤。然而,转移是一个十分复杂的过程。首先肿瘤细胞需从原发肿瘤中游离下来,然后穿入血管或淋巴管而进入血流,随血流到达靶器官,存活下来,并进行增殖。 Metastasis refers to the process by which malignant cells spread from a primary tumor to other tissues and organs to form a secondary tumor. The occurrence of metastases is considered to be undoubted evidence of the nature of the tumor. Metastasis often leads to the death of a patient. Therefore, if metastasis can be controlled, the risk of malignancy can be reduced to that of a benign tumor. However, the transfer is a very complicated process. First, the tumor cells need to be detached from the primary tumor, then penetrate the blood vessel or lymphatic vessel to enter the bloodstream, reach the target organ with the bloodstream, survive, and proliferate.