Detection of DNA amplification in human renal cell carcinoma cell lines using restriction landmark genomic scanning

Gene amplification, which has often been observed in various human cancers, appears to be associated with the development and progression of malignant phenotypes. However, in renal cell carcinoma (RCC), conventional analytic methods requiring specific primers and probes have revealed infrequent amplification of known oncogenes. We attempted to determine if gene amplification was truly uncommon in RCC. The genomic DNAs extracted from 5 human RCC cell lines were examined by restriction landmark genomic scanning (RLGS), a two-dimensional gel analysis which allows evaluation of approximately 2,000 radiolabelled DNA fragments. By this method, we detected 24 distinct spots commonly amplified in at least 2 RCC cell lines compared to normal kidneys. Comparing the present results with chromosomal assigned-RLGS, approximately one half of these DNA fragments proved to be located on chromosome 2, 5 or 7. Our data suggest that amplification of unknown genes is likely to occur in RCC cell lines.