A comparison of flow cytometric DNA analyses of fresh and fixed squamous cell carcinomas.

Aberrations in chromosome number, ploidy abnormalities, have been associated with malignancy and are predictive of outcome. Automated flow cytometry has made DNA analysis applicable to many solid tumors. Analysis can be performed on fixed specimens, allowing archival retrieval. The techniques, however, are unique and must be individually tested for each tumor type. Presently, few studies have been applied to head and neck cancers. This series of flow cytometric DNA analyses compares the results of 17 fresh and fixed head and neck squamous cell carcinoma specimens. Aneuploidy was present to a significant degree (47%). The method produced interpretable results in 100% of cases, with 100% reproducibility. Fresh and fixed tumor specimens yielded comparable results 76% of the time and, in fact, interpretability of fixed specimens was superior. This series demonstrates a practical and accurate flow cytometric DNA assay for fixed squamous cell carcinoma specimens, facilitating rapid retrospective ploidy analysis.