Genetic changes during mouse skin tumorigenesis.

This paper describes specific genetic changes involving chromosome 7 in mouse skin tumors, the most important consequence of which appears to be an alteration in the allelic balance of normal and mutant H-ras genes. The use of restriction-fragment-length polymorphisms in F1 hybrid mice demonstrates that trisomy of chromosome 7 is an early event preceding papilloma formation, and further events, such as mitotic recombination, seem to occur during progression to malignant carcinomas. There is some evidence of a tumor-suppressor locus situated on chromosome 7.