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

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