[Detection of intratumoral DNA heterogeneity in primary lung cancer using a multiple sampling method]

The nuclear DNA contents of 18 freshly resected specimens of primary lung cancer tissue were determined by flow cytometry with a multiple sampling method. A DNA aneuploidy pattern was observed in all cases. In three cases, a diploid DNA pattern was observed along with abnormal DNA stem lines. Twelve cases (66%) had two or more abnormal DNA stem lines, and were classified as DNA multiploidy. The frequencies of DNA aneuploidy and DNA multiploidy were higher than in previously reported studies. Intratumoral DNA heterogeneity was observed in 10 cases (55%). Three of these were a mixture of DNA diploidy and DNA aneuploidy, and the other seven were a mixture of DNA aneuploidy and DNA multiploidy. If multiple sampling had not been performed in these cases, their ploidy patterns would have been misinterpreted. We conclude that multiple sampling is important in determining the precise DNA ploidy patterns of primary lung cancers.