The fragments of cell plasma membranes of two lines of metastatic tumour of A/He mice (lung adenocarcinoma--LA-cells and hepatoma HA-1--HA-cells) were used to prepare "hybrid" vesicles (LA- and HA-liposomes). Incorporation of the fragments of LA-cells into the bilayer vesicle increased the binding of LA-liposomes with lung almost by an order of magnitude, their trapping by liver being noticeably decreased. HA-liposomes were retained in the liver in larger amounts than the model phospholipid liposomes. It is assumed that the specificity of metastatic spreading into an organ is associated with the interaction of the plasma membrane of the tumour cells with the apical membrane of the target organ endothelium
