Recurrent gene amplifications in human type I endometrial adenocarcinoma detected by fluorescence in situ hybridization.

Determining what genes are actively involved in tumor development is important, because they may provide targets for directed therapy. Human tumors are greatly heterogeneous with respect to etiology and genetic background, which complicates the identification of common genetic aberrations. In contrast, genetic and environmental variation can be in part controlled in experimental animals, which facilitates identification of the important changes. In inbred BDII rats, which are genetically predisposed to endometrial adenocarcinomas (EAC), certain chromosome regions exhibit recurrent amplification in the tumors. Previous CGH analysis had shown that a subset of human EAC tumors exhibited increased copy numbers in the homologous chromosomal regions, located in human 2p21∼p25 and 7q21∼q31. Using fluorescence in situ hybridization analysis on imprints from 13 human EAC tumors, we determined the average copy numbers of each of 15 probes derived from cancer-related genes situated in these chromosome regions. Among the genes analyzed, those most often targeted by amplification were SDC1 and CYP1B1 in 2p21∼p25 and CDK6 and MET in 7q21∼q31, but all of the 15 genes tested were found to be amplified in at least two tumors.