Intratumoral heterogeneity of DNA content in lung cancer.

Heterogeneity of DNA content was analyzed in 208 samples from 20 resected lung tumors. Only one carcinoma was homogeneously diploid, but the others had DNA aneuploidy in at least some tissue samples. Eighteen tumors (90%) had varying degrees of heterogeneity of DNA content. Over half of these could have been mislabeled as diploid if the tumors had not been widely sampled. The importance of adequate sampling in assessing ploidy status of lung tumors is emphasized.