TUMOR-CELLS INDUCED BY THE V-SRC ONCOGENE ARE HETEROGENEOUS FOR EXPRESSION OF MARKERS OF MESENCHYME DIFFERENTIATION

The observation that v-src-induced tumors contain tumor cells of diffe ring morphology, notably fibroblastoid or polygonal, raised the questi on as to whether the tumor cells are also heterogeneous with respect t o expression of markers of cellular differentiation. Of the markers te sted here, consistent reactivity for tumor tissue was noted only for a ntibody probes reactive to muscle actin (HHF35, alpha sm-1) or to proc ollagen type I(SP1. D8); for any given tumor, whether induced by v-src DNA or by Rous sarcoma virus, each of these markers was found only in a subpopulation of tumor cells. The observation of marker heterogenei ty in the one v-src DNA-induced tumor examined here that typed as mono clonal suggests that v-src-induced transformation is consonant with a degree of plasticity in the phenotypes of the clonal progeny of a sing le transformant.