Detection of stable chromosome aberrations by FISH in A-bomb survivors: comparison with previous solid Giemsa staining data on the same 230 individuals

Purpose: To evaluate the relative abilities of the solid Giemsa staining (conventional) and fluorescence in situ hybridization (FISH) methods in the detection of stable chromosome aberrations in the peripheral blood lymphocytes of A-bomb Survivors, Materials and methods: Lymphocytes from a total of 230 A-bomb survivors for whom prior chromosome aberration data had been obtained by the conventional method were recently examined afresh using FISH in which chromosomes 1, 2 and 4 were Painted with composite probes, Results: It was found that the early use of the solid Giemsa staining method had allowed the detection of translocations with a mean frequency of 73% of the value for the genome-equivalent, translocation frequency (F-G) that vas now obtained using FISH. The disparity may at least in part be due to the reciprocal exchange of seemingly identical amount of chromosome material; such exchanges call escape detection by the conventional method but call be readily identified using FISH. Conclusion: It has previously been established that the Conventional method can detect about 20% of radiatian-induced translocations as abnormal monocentric chromosomes. Present results indicate that all additional 50% call be detected if proper karyotyping is conducted and the remaining 30% are not likely to be detected unless FISH or banding methods are used. Thus, solid Giemsa staining accompanied by karyotyping may not be quite as unsuitable as is generally assumed for retrospective biodosimetry analyses, which deal mainly with stable aberrations.