Mutagenic virus replication in human tumor cells.

Herpes simplex virus was grown in different lines of human tumor and normal cells. The progeny virus was assayed for resistance to iododeoxycytidine, an indicator of a forward mutation in the virus genome. Virus grown in cells from 4 of 5 tumor lines demonstrated greater fractions mutated to iododeoxycytidine resistance than did virus grown in 7 normal human skin cell lines. The data indicate that some lines of human tumor cells modify the herpesvirus replication process, making it more mutagenic. In 2 cases of osteosarcoma patients, normal skin fibroblasts of the patients yielded normal levels of mutagenesis, while their tumor cells gave enhanced mutagenesis.