Intratumoral DNA content variability. A study of non-small cell lung cancer

Twenty-eight resected primary non-small cell lung carcinomas were studied for intratumoral DNA variability by flow cytometry (FCM). Three separate tissue specimens from each resected tumor were divided equally for FCM analysis and histologic evaluation. FCM analysis also was performed on fine-needle aspirates (FNAs) from the center of the resected tumor. Histologically, there were 8 squamous carcinomas, 19 adenocarcinomas, and 1 large cell carcinoma. Twenty-three tumors (82%) were aneuploid, and 5 (18%) were diploid. The DNA index in aneuploid neoplasms ranged from 0.91 to 3.30 (mean, 1.64). All 5 diploid and 19 (83%) of the (23) aneuploid neoplasms manifested intratumoral DNA stability. Four (17%) of the aneuploid tumors showed regional DNA heterogeneity expressed as additional stemlines in at least one sample. The FNA yield was sufficient in 21 cases and inadequate for complete analysis in 7 cases. In general, good correlation between FNA and tissue analysis was obtained. However, in three of the aneuploid neoplasms, FNA materials did not reveal an additional nondominant stemline, as noted in the tissue specimens. The authors attribute this finding to a dilutional factor in the aspiration material. The authors conclude that most non-small cell lung carcinomas express DNA stability; FNA provides adequate cellular material for FCM in most cases.