[The DNA ploidy in squamous cell carcinomas of the mouth floor determined by flow cytometry].

The cellular DNA content of 90 primary squamous cell carcinomas of the floor of mouth was determined by flow cytometry. Aneuploid cell lines were detected in 86% of the cases. The proportion of diploid carcinomas decreased with size (T1: 63%, T2: 11%, T3: 7%) and histologic grade (G1: 17%, G2: 16%, G3: 9%). Only 15% of the diploid, but 61% of the aneuploid tumors showed evidence of lymph node involvement. A 96% sensitivity of the test and a negative predictive value of 85% emphasize the prognostic importance of DNA ploidy in the primary tumor to evaluate the risk of subclinical dissemination.