Micronucleus frequency in Gomel (Belarus) children affected and not affected by thyroid cancer

Cytogenetic monitoring was carried out on a group of children from Gomel (B elarus), one of the areas most severely affected by radioactive contaminati on following the accident at the Chernobyl nuclear power plant, in 1986. We performed the micronucleus test (MN) in binucleated lymphocytes of 42 chil dren (mean age: 11 +/- 2.34 years), 16 of whom were affected by thyroid gla nd tumor. Thirty healthy children Living in Pisa (mean age: 14.96 +/- 2.17 years) were enrolled in the study as controls. Thyroid tumor affected child ren Living in Gomel showed a statistically significant increase in the freq uency of micronucleated cells as compared with the healthy children from Pi sa. Moreover, a significant correlation was found between MN frequency and both the presence of tumor and higher Cs-137 contamination. In addition, hi gher Cs-137 contamination was more frequently observed in tumor affected ch ildren. These results suggest that the increased MN frequency is attributab le more to Cs-137 contamination rather than to the presence of the tumor it self. (C) 1999 Elsevier Science B.V. AII rights reserved.