Comparison of DNA flow cytometry and fluorescence in situ hybridization with a set of 10 chromosome-specific DNA probes in four head and neck carcinomas

Abstract Four squamous cell carcinomas of the oral cavity were simultaneously analysed by DNA flow cytometry (FCM) and fluorescence in situ hybridization (FISH) with alpha-telomeric DNA probes specific for chromosomes 1, 2, 3, 6, 7, 8, 10, 12, 17, and X. Nuclei with 2 hybridization signals for most chromosomes were in agreement with flow cytometric DNA content in a diploid tumor, but a monosomy 8 for half of the cells indicated a tumor clone with an aberrant chromosome 8. Aberrations of virtually all chromosomes were found in 3 aneuploid tumors. Comparing the relative numbers of disomal and aneusomal nuclei with the corresponding proportions of DNA diploid and aneuploid sample cells provided evidence that the flow cytometrically diploid cell population of an aneuploid tumor consisted of both karyotypically normal and abnormal cells. Although there was a high degree of concordance between aberrant DNA content and magnitude of chromosomal aberration, discrepancies between both methods suggested a notable clonal heterogeneity in aneuploid tumor cell populations. These results demonstrate that a simultaneous application of DNA flow cytometry contributes to broaden the utility of interphase cytogenetics.