Flow cytometric evaluation of chemosensitive and chemoresistant head and neck tumors. For patients with head and neck squamous carcinoma, a clinical response to induction chemotherapy has correlated with a survival advantage. Similarly, patients with diploid tumors have displayed a survival advantage when compared with patients with aneuploid tumors. This study examined DNA content in 33 patients who had undergone induction chemotherapy as part of two clinical protocols to determine if there was a correlation between the patients with diploid tumors and the patients with a clinical response to chemotherapy. Although patients with stage III tumors had a longer disease-free survival than stage IV patients (p less than 0.0002), the addition of DNA content information did not improve the ability to predict response. Specifically, there was no correlation between DNA content and the response to chemotherapy. In addition, for this group of patients, a diploid DNA content was not correlated with a survival advantage. We conclude that DNA content information did not add significantly to the prediction of clinical outcome in these patients who received induction chemotherapy. 