FISH-based analysis of radiation-induced chromosomal aberrations using different nomenclature systems

Comparison of three nomenclature systems for the description of chromosomal aberrations involving painted chromosomes (PAINT, S&S and a conventional method) by parallel application to one data set.

Radiation-induced (3 Gy 220 kV X-rays) chromosome aberrations in human lymphocytes were analysed by FISH-painting of seven single chromosomes (1, 3, 6, 7, 8, 10 and 14) simultaneously with a pancentromeric probe.

Each system is based on different prerequisites and uses different criteria for the classification and quantification of structural chromosome aberrations. Due to the frequent occurrence of complex exchanges (resulting from > or = 3 breaks on > or = 2 chromosomes), standard cytogenetic scoring criteria used for solid-stained preparations are inadequate for a precise and reproducible classification of aberrant painting patterns. S&S is particularly suitable if a mechanistic interpretation of aberration origins is required. The descriptive terminology of PAINT enables a rapid, reproducible description, even of most extensively rearranged chromosomes by classifying each abnormal painting pattern individually.

A modification of PAINT criteria, allowing also for mechanistic aspects, would be most advantageous for practical application.