Specificity of arrest, survival, and growth of selected metastatic variant cell lines.

Animal tumor models for blood-borne metastasis have been developed by in vitro cloning or in vivo selection of malignant tumor cell populations to obtain organ-preferring variant tumor cell lines with altered arrest, survival, invasion, and growth properties. Selection and some tumor cell characteristics of lung-, brain-, and ovary-colonizing metastatic B16 melanoma, liver-colonizing RAW114 lymphosarcoma, and lung-colonizing MSV3T3 vasoformative sarcoma variant lines will be discussed along with additional data, suggesting that tumor cells of varying malignant potential preeexist in the unselected tumor population.