Changes in adhesive properties of tumor cells do not necessarily influence metastasizing capacity.

BSp6S and BSp73AS are two rat tumors which grow locally after intra-footpad (ifp) application. BSp73ASML and BSp6AS are variants, which metastasize via the lymphatics. Both variants have lost adherence properties, as shown by in vitro culture on plastic surfaces, suggesting that loss of adherence may be accompanied by increased metastasizing capacity. However, after growth of BSp6S and BSp73AS in vitro on poly(2-hydroxyethylmethacrylate) (polyHEMA)-coated plates, which resulted in loss of adherence and spreading, and subsequent intravenous (iv) or ifp injection of non-adherent tumor cells into syngeneic rats, metastasizing capacity was not increased. It is concluded that loss of adherence may facilitate metastatic spread, but certainly is not sufficient for initiation.