Involvement of specific chromosomes in radiation-induced rearrangements detected by fluorescence in situ hybridization (FISH).

We investigated the involvement of chromosomes in dicentrics and translocations in human peripheral blood lymphocytes exposed to X-rays in vitro. Chromosomes 2, 4, 8, 13, 15, 16, and 22 were analyzed in three cocktails of different combinations using whole chromosome probes (WCP) with the fluorescence in situ hybridization (FISH)-painting technique. The results showed overexpression of chromosomes 2, 8, and 22 in translocation, the majority being of the complete type. Chromosome 4 was underrepresented in translocation formation in both combinations, that is, 2 + 4 + 8 in cocktail I and 4 + 13 + 22 in cocktail II. Its participation in dicentric production was in good agreement with its DNA content in association with 2, 4, and 8, whereas it was underexpressed in the combination of 4 + 13 + 22. DNA-proportional involvement was noticed with chromosomes 13 and 16 in all exchange aberrations. Underexpression of chromosome 15 was observed in translocation, which is contradictory to its overexpression in dicentric formation. The participation of chromosome 22 was predominant for both translocations and dicentrics, compared with its DNA content. The overall observation of our study supports the assumption of DNA-proportional distribution of Lucas et al. However, more data are required for chromosomes 4, 8, 15, and 22 in combination with other chromosomes.