Abstract
Human cell hybrids derived from malignant HeLa cervical cancer and normal fibroblast parental cells expressed many of the transformed properties of the HeLa parent but their tumor-producing capability was suppressed. Hybrids derived from HeLa/HeLa fusions retained their transformed and malignant phenotypes. An apparent separation of the control of the transformed vs. malignant phenotype is indicated. Several transformed properties including lack of density-dependent inhibition of growth, lectin agglutination, lowered requirement for serum growth factors, and anchorage independence are expressed coordinately in the nontumorigenic hybrids. This finding suggests that none of these properties by themselves, or in concert, endows a cell with tumorigenic potential.