Background: Dihydropyrimidine dehydrogenase (DPD) activity in tumor tissues is thought to play an important role in the antitumor effect of 5-fluorouracil (FU). In order to define 5-FU-resistant nonsmall-cell lung cancer, we assessed the DPD level in tumor tissues with an enzyme immunoassay.
Methods: Using a sandwich enzyme immunoassay, the DPD level in lung cancer tissues was quantitatively measured in 52 patients with primary lung cancer who had undergone a pulmonary lobectomy.
Results: The mean DPD level in tumor tissues was significantly higher than that in normal lung tissues (194 units/mg protein vs 53 units/mg protein; P < 0.001). The DPD level in tumor tissues correlated with neither sex nor age. Although there was no difference in the DPD level according to the grade of differentiation, squamous cell carcinoma exhibited a significantly lower level of DPD than adenocarcinoma. However, the DPD level in tumor tissues did not correlate with the advance of disease.
Conclusion: Compared with adenocarcinoma, squamous cell carcinoma might be a favorable target for 5-FU-based chemotherapy in the treatment of nonsmall-cell lung cancer.