[Analysis of DNA ploidy using fresh frozen tissues from head and neck squamous cell carcinomas]

The DNA ploidy of fresh frozen tissues from head and neck squamous cell carcinomas was determined by flow cytometry, with the aim of investigating whether DNA ploidy correlates with various clinical and pathological parameters. The subjects were 51 patients who had undergone radical surgery in our department. The DNA ploidy pattern was classified into three types, diploid, single aneuploid and multiploid, according to the DNA index and the DNA histogram. This is our original classification. No particular correlation could be detected between the DNA ploidy pattern and sex, age, primary tumor site or disease stage. The degree of tissue differentiation tended to be poorer in aneuploid than in diploid tissues. The efficacy of chemotherapy was higher in aneuploid than in diploid cases. The recurrence rate was significantly lower in diploid than in multiploid cases. When disease stage, degree of histological differentiation, the efficacy of chemotherapy and the DNA ploidy pattern were subjected to multivariate analysis for correlation with prognosis, the DNA ploidy pattern showed the highest correlation. Our results suggest that the DNA ploidy, as analyzed by flow cytometry, can serve as useful prognostic factor.