Follow-up on flow cytometric DNA analysis of squamous cell carcinoma of the tongue.

Preliminary data from this institution suggested that flow cytometric DNA analysis was an objective prognostic indicator in archival localized squamous cell carcinoma of the tongue. Technical improvements were made, including analysis of tumor, normal tissue, and a combination of the two; standardized cursor placement; mathematic determination of tetraploid populations; and development of a statistical analysis. A larger number of patients (60) with this disease were reviewed. DNA content was related to disease-free survival, local recurrence, regional metastasis, and incidence of second primary tumors. There was no significant difference between aneuploid and diploid tumors with respect to the variables analyzed. We believe these technical improvements will enhance flow cytometric DNA analysis of paraffin-embedded tissues. However, in this retrospective review of localized squamous cell carcinoma of the tongue, DNA analysis was not a valuable prognostic indicator. Only prospective studies will address this issue.

Technical and statistical improvements for flow cytometric DNA analysis of paraffin-embedded tissue.

Flow cytometric DNA analysis of paraffin-embedded solid tumors has permitted review of large series of archival tissue in attempts to relate abnormal DNA content to prognosis. Limitations of the technique include: 1) a laborious, time-consuming procedure; 2) variation in technique between laboratories; and 3) lack of an objective method of computing DNA indices. Critical evaluation of our technique has shortened the time involved in dewaxing and rehydration, selectively utilized patient's own normal tissue as the internal standard, proved reproducibility of stored specimens, standardized DNA index computation, and developed a statistical analysis to confirm aneuploidy. These technical improvements and the development of a statistical analysis provide a way to shorten the procedure time and standardize the data generated from flow cytometric DNA analysis so as to improve the quality of retrospective reviews of paraffin-embedded tumors and accelerate the definition of flow cytometry's role as a prognostic indicator.