Introduction of human chromosome 11 via microcell transfer controls tumorigenic expression of HeLa cells.

Abstract
Both tumorigenic segregant HeLa X human fibroblast hybrids and tumorigenic HeLa (D98/AH‐2) cells can be converted to a non‐tumorigenic state following introduction of a single copy of a fibroblast t(X;11) chromosome. The translocated chromosome contains approximately 95% of the 11 chromosome and the q26‐qter portion of the X chromosome which contains the hypoxanthine guanine phosphoribosyl transferase (HPRT) gene. Introduction of a human X chromosome has no effect on tumorigenic expression. Suppression of tumorigenicity is relieved by selecting cells which have lost the t(X;11) chromosome by growth in medium containing 6‐thioguanine (6‐TG). Further, reintroduction of the t(X;11) chromosome into tumorigenic 6TGR cells again suppresses tumorigenicity. Thus, the introduction of a single copy of a human chromosome 11 is sufficient to completely suppress the tumorigenic phenotype of HeLa cells and is suggestive of the presence of tumor‐suppressor gene(s) on this chromosome.