Novel susceptibility locus for mouse hepatomas: evidence for a conserved tumor suppressor gene.

We have identified previously a putative tumor suppressor gene (TSG) locus at human chromosome (hchr) 7q31 showing that it is altered in a variety of human epithelial tumors. To determine whether this TSG is conserved in mice, we studied loss of heterozygosity (LOH) in chemically induced mouse liver adenomas. The LOH analysis was performed by polymerase chain reaction amplification of 17 (CA)n microsatellite repeats on mouse chromosome (mchr) 6 A2-C3. Ninety-six of 106 cases (90.6%) had LOH at D6Mit50, and 89.5% had LOH at D6Mit179. These two loci are 0.2 cM apart on mchr 6A2. Another high-LOH site was found in the C3 band. The high incidence of LOH in the 7q-homologous segment of mchr 6 indicates that the human TSG is conserved and is involved in the development of hepatomas.