Cytogenetic studies were performed on 80 pediatric cancer patients to observe the
chromosomal damage, both quantitative and qualitative, induced by chemotherapy.
Peripheral blood lymphocytes (PBL) (n = 127) were obtained at diagnosis, during
treatment, at remission, and at relapse, and chromosome analysis performed
utilizing G-banding standard procedures. The results show a significant increase
in the number of altered karyotypes (P = 0.03) in the samples during treatment,
returning to values that were similar to those at diagnosis at 2-year remission.
Most of the chromosomal aberrations (CA) detected during the chemotherapy
regimens were nonclonal, unbalanced (75%), and involved chromosomes 1, 3, 5, 6,
11, 12, 16, and 17 most frequently. There was also a marked increase of CA in
samples at relapse with very similar features (type and distribution) to those
detected during treatment. There was a good correlation between the chromosomal
breakpoints in our series and fragile sites (58%), oncogene (75%), and tumor
suppressor gene (33%) loci described in the literature. The results obtained
suggest that cytostatic drugs induce a transient increase in chromosome fragility
occurring at several cancer-associated breakpoints.