[p53 alterations and chromosome 17 aberrations in non-small cell lung cancer]

We studied the relationship between DNA index, numerical abberation of chromosome 17 and alterations of the p53 gene in 23 non-small cell lung cancers. Diploid and aneuploid cells from 23 non-small cell lung cancer with DNA aneuploidy were flow sorted into each cell population using FACStar(plus). They were examined by PCR-SSCP analysis for p53 mutation and by microsatellite analysis for loss of heterozygosity at TP53 locus (17p13.1). They were also analyzed by FISH for copy number of chromosome 17. p53 mutations were found in aneuploid cells from the 11 cases (48%). Among them, 8 cases were informative at TP53 locus, and all showed loss of heterozygosity. Aneuploid cells from 16 cases exhibited gain of chromosome 17 copy number in FISH analysis. DNA index was significantly associated with th mean copy number of chromosome 17, suggesting that the number of chromosome 17 changed with DNA index. There were no associations between p53 mutation and DNA index or mean copy number of chromosome 17. In some cases, we also analyzed structural abberation of short arm of chromosome 17 by FISH using p53-cosmid (17p13.1) and Distal 17p (17p13.3-ptel) probes. The p53 gene located on the increased chromosome 17 was lost due to point mutation or deletion of 17p.