[Invasion, metastases of solid tumors. Interaction of tumor cells with tissue and vascular basement membranes].

Since early antiquity malignant tumors have been recognized and characterized by: 1) their particular local-regional invasive properties. Developing irregularly from the primary tumor mass, the invasion of adjacent tissues often displays classical crab-like images which distinguish, macroscopically and microscopically, malignant tumors from benign tumors. 2) their metastatic capacities. Even though they have been taught since the time of Hippocrates, the specific clinical characteristics of malignant tumors have only recently been apprehended and studied on cellular and biochemical levels. The development of the metastatic phenomenon is a complex chain of events limited to only a few tumor subpopulations. Like every biological study knowledge has progressed over the past years only by concentration of efforts on some of these stages: Invasion associated with disorganization and destruction of basement membranes; Migration of metastatic tumor cells in the stroma and bridging of vascular basal membranes; Colonization of target tissues by recognition and penetration of specific vascular membranes, establishment and concentric development within these tissues. These three stages result from successive interactions between multiple cellular and biochemical phenomena. This review is a schema of our present knowledge of tumor invasion, and more precisely of that concerning the relations between tumor cells and extracellular matrices, particularly basal membranes, leading to a definition of the cellular phenotype with a high metastatic potential.