metastasis /mətas″təsis/ pl. metastases [Gk, meta + stasis, standing] , 1. an active process by which tumor cells move from the primary location of a cancer by severing connections from the original cell group and establishing remote colonies. Because malignant tumors have no enclosing capsule, cells may escape, become emboli, and be transported by the lymphatic circulation or the bloodstream to implant in lymph nodes and other organs far from the primary tumor. 2. a tumor that develops away from the site of origin. Compare anaplasia. −metastatic, adj., −metastasize, v.
