The measurement of the intra-tumoral level of
thymidylate synthetase (TS), and
dihydropyrimidine dehydrogenase (DPD), may be useful in predicting
tumor sensitivity to
5-fluorouracil (5-FU). In this study, we examined the
mRNA levels of DPD and TS in 28
oral squamous cell carcinomas (SCC), and 22 salivary gland
tumors by semi-quantitative reverse transcription polymerase chain reaction. Then we examined the correlation of the responsiveness of the patients with oral SCC to
5-FU with the intra-tumoral levels of DPD and TS
mRNA. All specimens were obtained at the biopsy before treatment, and then the patients were treated by
oral administration of a
5-FU compound (UFT), the irradiation of
cobalt-60 (upto 60 Gy) and injection of an immuno-potentiator (OK-432). Intra-tumoral levels of DPD
mRNA in the patients who showed CR (complete response) and PR (partial response) were significantly lower than those in the patients who showed NC (no change). However, intra-tumoral levels of DPD
mRNA did not correlate with the local recurrence of the
tumor during the observation period after initial treatment with or without surgical resection of the
residual tumors. On the other hand, TS
mRNA levels in the
tumors did not correlate with any clinico-pathological parameters. These observations suggest that intra-tumoral levels of DPD
mRNA may predict the
tumor response to 5-FU-based chemo-immuno-
radiation therapy in the patients with oral SCC.