Clonal evolution of a radon-induced rat lung tumor

Radon gas may represent a source of pulmonary radio-contamination either in mine or in domestic conditions. Since epidemiological studies are controve rsial, as long as biological markers of the exposure to such agents will no t be identified, the question will remain open. We have previously shown a direct dose-dependant relationship between lung cancer occurrence and radon inhalation of rats. In this study, we report a cytogenetic study of a rado n-induced rat lung tumor. Chromosome banding and chromosome specific painti ngs were performed on cultures of both fresh and xenografted tumors. We fou nd by analyzing 17 sub-clones that all karyotypes presented a translocation involving rat chromosomes (RNO) 8 and 20, and a terminal deletion of RNO 1 5p suggesting a monoclonal origin of this tumor. RNO 15 is homologous to nu merous human chromosomes (HSA), in particular to HSA 3p14.2, 3p22-p24.1 and 3p24.2-p24.3, this human chromosome being frequently lost in human lung ca rcinomas. Besides sharing chromosome alteration involving common features w ith those found in human lung cancer, this rat lung carcinoma represents a useful model to study tumor progression with respect to clonal evolution. ( C) 2001 Elsevier Science Inc. AII rights reserved.