Loss of p53 in benzene-induced thymic lymphomas in p53+/- mice: Evidence of chromosomal recombination

The purpose of this study was to examine the role of chromosomal recombinat ion in mediating p53 loss in benzene-induced thymic lymphomas in C57BL/6-Tr p53 haploinsufficient (N5) mice (p53+/- mice). We characterized loss of het erozygosity (LOH) on chromosome 11 using seven microsatellite markers in 27 benzene-induced and 6 spontaneous thymic lymphomas, Eleven patterns of LOH were found between the induced and spontaneous tumors,,vith only one patte rn being in common between the tumor groups. Nearly 90% (24 of 27) of benze ne-induced tumors exhibited loss of the functional p53 allele locus, and 83 % (20 of 24) of these tumors retained two copies of the disrupted p53 allel e, The results indicate that benzene induces a high frequency of LOH on chr omosome 11 in p53+/- mice, likely mediated by aberrant chromosomal recombin ation.