Dissociation of anchorage independence form tumorigenicity in human cell hybrids

The association between anchorage independence and tumorigenicity was examined using a series of intraspecific human cell hybrids. The cell lines represented non-tumorigenic HeLa/fibroblast hybrids and tumorigenic segregants derived from them. These segregants had lost no more than 5% of the original chromosome complement. Both non-tumorigenic and tumorigenic cell populations formed colonies in methyl cellulose. The relative size of the colonies seemed to be inherited as a stable trait. Serial cloning of nontumorigenic hybrids in methyl cellulose led to an enhanced efficiency of colony formation but no selection for tumorigenic segregants. Thus, the property of anchorage independence is clearly dissociated from tumorigenicity in this human cell system. An ancillary observation was the chromosomal stability of the hybrids over many population doublings. This intraspecific human cell model therefore provides a genotypically and phenotypically stable system for examination of the genetic control of transformation and neoplasia.