Non-random distribution of cyclophosphamide-induced chromosome breaks.

The mutagenic effect of Endoxan on human lymphocytes was studied both in vivo and in vitro by the QM banding technique following the usual Giemsa stain. Chromatid breaks and interchanges were observed after applications in vivo. Chromosome aberrations were not distributed at random, because of a significant increase in the number of breaks on chromosome 15. The breakpoints affected the weakly fluorescent region on the chromosomes more than the strongly fluorescent region.