Absence of delayed chromosomal instability in a normal human fibroblast cell line after I-125 iododeoxyuridine

Purpose: To seek the delayed appearance of chromosomal abnormalities in hum an fibroblasts exposed to the Auger electron emitter I-125. Materials and methods: Normal untransformed human fibroblasts, HF19, were e xposed to a concentration of [I-125]IUdR, which allowed the survival of 37% of clonogens. Chromosomal analysis using both conventional Giemsa and fluo rescence in situ hybridization (FISH) was undertaken on non-clonal bulk cul tures from 2 to 39 days after treatment. Results: The data show a declining level of unstable aberrations in the pro geny of HF19 fibroblasts exposed to [I-125]IUdR, eventually reaching contro l levels. Conclusions: The results provide evidence that [I-125]IUdR does not induce ongoing chromosomal instability in long-term culture, and gives further sup port to the use of Auger-electron emitting radionuclides in the treatment a nd diagnosis of tumours.