Marker Polypeptides Distinguishing between Cancer Cell Clones with High and Low Potential for Spontaneous Metastasis in Murine Fibrosarcoma Cells¹

Consistent differences in expression of specific proteins were observed between numerous cancer cell clones with high and low potential for spontaneous metastasis. Seventeen clones from two unrelated murine fibrosarcomas were examined concomitantly for spontaneous formation of lung metastases and for occurrence of individual polypeptide differences by high resolution two-dimensional gel electrophoresis. One of the identified marker polypeptides, designated Hi:2, was very strongly expressed by all 10 strongly metastatic clones, but was absent from 6 and only weakly expressed by one of the 7 weakly metastatic clones. Another marker polypeptide, designated Lo:6, was consistently most strongly expressed by the weakly metastatic clones. Among the approximately 2000 individually separated cellular polypeptides, only these two marker polypeptides consistently distinguished between the strongly and weakly metastatic clones from both fibrosarcomas. Five other polypeptides also distinguished between highly and weakly metastatic clones, but not as stringently.