Frequent loss of heterozygosity on chromosomes 4, 12 and 19 in radiation-induced lymphomas in mice

We found frequent loss of heterozygosity (LOH) on chromosomes 4, 12 and 19 in radiation-induced lymphomas from (BALB/cHeA x STS/A) F-1 hybrid mice by allelotype analysis at polymorphic microsatellite loci. The incidences of L OH were 27% (20 of 74 lymphomas), 57% (42 of 74 lymphomas) and 50% (37 of 7 4 lymphomas) on chromosomes 4 (at D4Mit31), 12 (at D12Mit17) and 19 (at D19 Mit11), respectively. These frequent LOH regions are homologous to human ch romosomes 9p and Ip, chromosome 12q32.1 and chromosome 10q, respectively. S train-specific preferential allele loss was observed only on chromosome 4. However, no bias in the frequency of loss between alleles of maternal and p aternal origin was observed, indicating that genomic imprinting may not be predominantly involved in these lymphomas. The results suggest that these t hree regions might harbor tumor suppressor genes responsible for this lymph omagenesis. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.