Profiling of fluorouracil-related genes by microdissection technique in hepatocellular carcinoma

5-fluorouracil (5-FU)-related metabolic enzymes, including dihydropyrimidine dehydrogenase (DPD), thymidylate synthase (TS), thymidylate phosphorylase (TP), and orotate phosphoribosyl transferase (OPRT) are initial, rate-limiting enzymes in the metabolism of 5-FU. The therapeutic implications of these enzymes in hepatocellular carcinoma (HCC) remain poorly understood. We used a newly developed laser-captured microdissection technique combined with RNA extraction to examine the mRNA levels of 5-FU-related metabolic enzymes in HCC and adjacent liver tissue.

The study material comprised 43 paired specimens of HCC and adjacent liver tissue. The mRNA levels of 5-FU-related metabolic enzymes were quantified by real-time reverse-transcriptase polymerase chain reaction combined with laser-captured microdissection.

The DPD mRNA level in HCC (4.31 +/- 4.21) was lower than that in adjacent liver (6.53 +/- 2.93) (p < 0.001). The TS mRNA level in HCC (3.55 +/- 2.54) was higher than that in adjacent liver (1.90 +/- 0.11) p < 0.001). The TP and the OPRT mRNA levels did not differ significantly between HCC and adjacent liver. The TS mRNA level of HCC with portal invasion (4.47 +/- 2.76) was higher than that of HCC without portal invasion (2.71 +/- 1.96) (p = 0.015). The DPD mRNA level of HCC with septum formation (4.89 +/- 4.82) was significantly higher than that of HCC without septum formation (2.12 +/- 0.61) (p < 0.027). The OPRT mRNA level of poorly differentiated HCC (1.18 +/- 0.49) was lower than that of moderately or well-differentiated HCC (2.42 +/- 1.82) (p = 0.037).

The DPD mRNA level was lower and the TS mRNA level was higher in HCC than in adjacent liver. Our results will hopefully stimulate further investigations designed to optimize the use of 5-FU in patients with HCC.