CHROMOSOME SENSITIVITY TO BLEOMYCIN IN PATIENTS WITH DOMINANTLY INHERITED AND SPORADIC TUMORS

G2 chromosomal sensitivity to bleomycin (30 mug/ml) was tested in PHA- stimulated lymphocytes of healthy subjects and in patients with famili al and sporadic tumors. These were multiple endocrine neoplasias (MEN) types 1, 2A and 2B, familial medullar thyroid cancer, Recklinghausen neurofibromatosis type I, sporadic and hereditary malignant tumors, an d a preleukemic disorder, the myelodysplastic syndrome. Control subjec ts were either young (15-20), middle-aged (28-49) or old (70-83 years) . Cells from old healthy subjects and from subjects with MEN 1 showed increased sensitivity to clastogenic effects of bleomycin. All the rem aining investigated groups were insignificantly different from control s. Our data suggest that in contrast with recessively inherited syndro mes with chromosome instability the mutagen hypersensitivity, as evalu ated by the extent of chromosomal damage, is not a feature or most dom inantly inherited tumor syndromes.