Normal cytotoxic response of skin fibroblasts from patients with Li-Fraumeni familial cancer syndrome to DNA-damaging agents in vitro.

Skin fibroblasts from patients with the Li-Fraumeni familial cancer syndrome have been reported to show abnormalities in their response to X-irradiation. We have examined the response of fibroblasts from affected and nonaffected individuals in three families to treatment with four DNA-damaging agents: X-rays, UV light, N-methyl-N'-nitro-N-nitrosoguanidine, and mitomycin C. Test cells along with additional cell bank control strains were received coded and blinded. The same strains were studied on 2 or 3 separate occasions; each of these groups was coded differently. The cytotoxic effects of the four agents were examined by a colony formation assay. Sensitivity to the induction of chromosomal aberrations by X-rays was also measured. In all cases, the response of cells from affected individuals did not differ significantly from that of cells from unaffected (not a risk) family members nor of cell bank controls. The response of somatic cells from members of Li-Fraumeni cancer families to DNA-damaging agents does not appear to be a fruitful approach to the detection of at-risk individuals.