Genetic analysis of tumorigenesis: V. Chromosomal analysis of tumorigenic and nontumorigenic diploid chinese hamster cell lines.

The chromosomal constitution of four established diploid Chinese hamster embryo fibroblast (CHEF) cell lines is described. CHEF/18 exhibits anchorage-dependent growth and is not tumorigenic in nude mice. CHEF/16 has a high plating efficiency in methylcellulose and is highly tumorigenic in nude mice. Both CHEF/8 and CHEF/16 have a normal Giemsa banding pattern and constitutive heterochromatin distribution characteristic of normal diploid Chinese hamster cells and exhibit relatively little chromosomal variation within their cell populations. These results suggest that the nuclear changes responsible for tumorigenicity of CHEF/16 involve alterations below the level detectable by Giemsa banding analysis. Chromosome rearrangements were detected in two other CHEF cell lines; CHEF/205-30, a diploid, thioguanine-resistant derivative of CHEF/18, and CHEF/204-Bu 50, a diploid, 5-bromodeoxyuridine-resistant derivative of CHEF/16, which are being used as genetic markers in intraspecific somatic cell hybrids.