Heterogeneity of squamous cell carcinomas of the oral cavity studied by flow cytometry.

The DNA pattern was determined by flow cytometry in 76 samples from 16 squamous cell carcinomas of the oral cavity to assess intratumour DNA heterogeneity. Heterogeneous DNA content was found in 2 tumours (12%); both containing DNA diploid and DNA aneuploid cell clones. The remaining 14 tumours showed a homogeneous DNA distribution in the different specimens; 9 (56%) were diploid, 3 (19%) aneuploid and 2 (12%) were polyploid. The DNA non-diploid tumours were clinically more advanced than the DNA diploid ones (p less than 0.05). The tumour proliferation rate (fraction of cells in S-phase) was higher in aneuploid tumours than in diploid ones (p less than 0.01).