Fragile sites and neuroblastoma: fragile site at 1p13.1 and other points on lymphocyte chromosomes from patients and family members.

Fragile sites on lymphocyte chromosomes of 20 patients with neuroblastoma of different clinical stages and histologic differentiation were studied. A hitherto unknown break in the band p13.1 of chromosome #1 was found in a frequency of 3%-15% in nine cases. The same phenomenon was observed in three members of a neuroblastoma family. In another instance, this fragile site was also seen in the mother of a patient. Fragile sites were expressed when cells were cultured in folate-deprived medium and could be slightly enhanced in frequency by aphidicolin. Additional aphidicolin induced possible fragile sites hitherto unknown or not yet accepted by the HGM 8 were detected.