Fragile sites and chromosome instability: the distribution of breaks induced by cis-diamine-dichloro-platinum (II) in Fanconi anemia lymphocyte cultures.

The distribution of chromosome breaks induced by the antitumor drug cis-diamine-dichloroplatinum (II) in lymphocyte cultures from Fanconi anemia patients was analyzed. Breakpoints occurred nonrandomly over an arbitrarily defined human karyotype of 319 bands. These bands were classified according to either their banding pattern or their fragile site status (whether or not a fragile site of a given type is located at a chromosomal band). A significant involvement of G-light and fragile site bands was detected. The preferential occurrence of breaks at fragile site bands was limited to common fragile site bands (essentially of the aphidicolin-type).