转移恶性肿瘤细胞如自其原发部位脱离而被带至别处并在该处继续生长,形成一个或多个与原发肿瘤组织特性相同的新肿瘤,这一过程称为转移。其所形成的新肿瘤称为转移瘤。而转移瘤也可再行转移。瘤细胞之转移途径,不仅向邻近浸润侵袭,且可穿入血管或淋巴管进行远处转移。转移是恶性肿瘤最主要的特征之一,因为良性肿瘤不发生转移,很少例外。通常肿瘤恶性程度愈高,细胞分化愈差,浸润生长越快,其也更倾向于较早发生转移。但也有组织分化较好,却也可伴有 Metastatic cancer cells, e.g. detached from their primary site, are taken elsewhere and continue to grow there, forming one or more new tumors with the same characteristics as the primary tumor tissue. This process is called metastasis. The new tumor it forms is called a metastasis. Metastases can also be transferred. The metastatic pathway of tumor cells can not only infiltrate adjacent invaders, but also can penetrate the blood vessels or lymphatic vessels for distant metastasis. Metastasis is one of the most important features of malignant tumors because benign tumors do not metastasize, with few exceptions. In general, the higher the degree of malignancy of the tumor, the worse the cell differentiation, the faster the infiltration and growth, and it is more inclined to metastasize earlier. But there are also good organizational divisions, but they can also be accompanied by