The Expression of Glypican-3 in Colorectal Cancer

—Glypican-3 (GPC3), a heparan sulfate proteoglycan is an emerging tumor marker; its overexpression has been stated in several types of cancer such as hepatocellular carcinoma (HCC), melanoma and etc. In this study, the expression of the GPC3 mRNA was investigated in 61 human colorectal cancer (CRC) tissues and 61 normal adjacent tissues, using the real-time PCR assay. Using immunohistochemistry (IHC), the expression of the GPC3 protein was examined in the cases that showed a marked elevation in the expression of the GPC3 mRNA in the tumor tissues, compared to the normal tissues. A significant increase in the expression of the GPC3 gene was revealed in 49.2% of the cases of CRC tumors, compared to the normal adjacent tissues. The expression of the GPC3 mRNA was found to significantly correlate with the pathological differentiation and the age of the patients. Interestingly, a significant reduction in the expression of the GPC3 mRNA was found in the tumor tissues of the 16 patients, who underwent the neoadjuvant chemotherapy, compared to the normal adjacent tissues. Unexpectedly, the GPC3 protein was not detected by IHC in 30 tissues, exhibiting the upregulation in the expression of the GPC3 mRNA. Our results indicated that GPC3 could be expressed in the CRC tissues at the mRNA level, while its expression could not be found at the protein level.