Whole cell preparation of squamous cell carcinoma for cytometric analysis of DNA

To date, analysis of the DNA content of head and neck squamous cell carcinomas has relied on the homogenation of the entire tissue specimen and subsequent staining and quantitation of the naked nuclei. This methodology does not make allowance for the extremely variable nature of these tumors with respect to their cellular composition. Further, by destroying the cytoplasm and cell membranes, this methodology makes it impossible to distinguish the DNA content of the tumor cells from that of the background stromal and inflammatory cells. The authors present a methodology for the selective exclusion of inflammatory cell infiltrates from the DNA analysis of these tumors. Using this technique, it has been found that exclusion of the inflammatory cells allows the investigator to look more specifically at the malignant cell population. This has been most helpful in those samples in which the tumor cells have been diploid or near-diploid. With this technical refinement, the relationship between DNA ploidy and clinical prognosis may be more accurately assessed.