A pilot study of mRNA expressions of 5-fluorouracil pathway genes in peripheral blood mononuclear cells and tumor tissues in patients with lung adenocarcinoma

To assess whether early lung cancer prediction might be informed by an mRNA assay for 5-fluorouracil pathway genes in peripheral blood mononuclear cells (PBMNCs), we examined specimens taken from 51 adenocarcinoma patients and 38 controls (including six patients with benign tumors). PBMNCs and tumor-tissue specimens were taken for measurement of the mRNAs of various 5-fluorouracil pathway genes [thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), and orotate phosphoribosyl transferase (OPRT)]. By quantitative RT-PCR, all four mRNAs were detected in both PBMNCs and tumor tissues. In PBMNCs, TS mRNA/GAPDH mRNA levels were significantly higher in adenocarcinoma patients than in the controls, and significantly higher for pathological stages 2–4 and lymph-node involvement pN1–pN3 than for pathological stage 1 and pN0, respectively. No correlation between PBMNCs and tumor-tissue specimens was found for the level of any mRNA. Thus, the measurement of TS mRNA in PBMNCs might aid the diagnosis of lung adenocarcinoma.