[Significance of glypican-3 mRNA expression in hepatocellular carcinoma tissues and peripheral blood cells].

OBJECTIVE

To investigate the expressions of glypican-3 (GPC3) mRNA in hepatocellular carcinoma (HCC) tissues and peripheral blood cells (PBCs), and to determine the values of GPC3 mRNA in the diagnosis of HCC and HCC micrometastasis.

METHODS

Using semi-quantitative and nested reverse transcription polymerase chain reactions (RT-PCR), we detected the expressions of AFP and GPC3 genes in the tissues of 41 HCC, 41 paracancer and 52 non-HCC liver samples (41 far from HCC tissues and 11 normal liver tissues), and in the PBCs of 67 specimens from subjects.

RESULTS

The semi-quantitative RT-PCR displayed GPC3 mRNA was expressed in all samples of tissues and PBCs, and the relative intensities of its expressions in HCC, paracancer, non-HCC liver tissues were 78.9 +/- 35.5, 30.6 +/- 21.6, 23.8 +/- 15.5 respectively. The AFP mRNA expression values were 61.2 +/- 32.6, 31.5 +/- 23.6, and 21.2 +/- 15.9 respectively. The expression of each gene in HCC differed significantly from those in other two kinds of tissue samples (P < 0.01). The expressions of GPC3 mRNA and AFP mRNA, accounting for 80.5% and 63.4% in all the HCC tissues, were higher than their respective peak values in the tissues of non-HCC liver (+1.96s), but the expressions of at least one of the two genes was elevated in 92.7% of all the HCC tissues. There was a significant difference between combined detection of two genes and single AFP mRNA detection in HCC tissues (P < 0.01). Clinicopathologically, AFP mRNA was related with the grade of HCC and serum AFP, while GPC3 mRNA was related with not only the grade of HCC but also the invasion of HCC. The relative intensities of GPC3 mRNA expressions in PBCs of 67 specimens was 15.9 +/- 9.0, and GPC3 mRNA expressed in three kinds of tissue samples were all stronger than its counterparts in PBCs (P < 0.01). The GPC3 mRNA expression values in PBCs of the HCC group and the non-HCC group were respectively 16.1 +/- 8.3, 15.6 +/- 10.2, there was no significant difference between the two groups. Of the HCC metastasis group and the HCC non-metastasis group, the respective GPC3 mRNA expression values in PBCs were 16.0 +/- 9.0 and 16.3 +/- 7.7, there was also no significant difference between the two groups. The nested RT-PCR showed that the positive rates of AFP mRNA expressions in PBCs from the HCC group and the non-HCC group were 56.1% and 23.1%, and the difference between the two groups was significant (P = 0.011). The positive rates of AFP mRNA expressions in PBCs from the HCC metastasis group and the HCC non-metastasis group were 80.9% and 30.0%, and there was also a significant difference between the two groups (P = 0.002).

CONCLUSIONS

Although GPC3 mRNA is expressed broadly, it still may serve as a potential tissue biomarker in the diagnosis of HCC. Detecting the expression of the two genes in the tissues will improve the screening and diagnosis of HCC. GPC3 is prevalently transcribed in the PBCs, but we have not found any relationship between the GPC3 expression in PBCs and the metastasis or recurrence of hepatocellular carcinoma, thus we can not identify HCC micrometastasis with GPC3 mRNA.