中文摘要：

BACKGROUND:YKL-40 is a new biomarker with diagnostic value in many different cancers.Whether it may serve as a biomarker for hepatocellular carcinoma (HCC) is still unclear.This study aimed to examine the expression of YKL-40 in the serum and liver tissues of HCC patients and in HCC cell lines,in comparison with that in non-HCC liver disease patients and non-tumor hepatic cell lines,respectively.METHODS:Immunohistochemical staining was used to detect YKL-40 protein expression in liver biopsy specimens from 8 HCC patients.ELISA was used to assess the serum YKL-40 level in 90 HCC patients,90 inactive HBsAg carrier (IHC) patients with normal liver functions,and 90 liver cirrhosis patients.Real-time PCR was used to determine the YKL-40 mRNA expression in three HCC cell lines and two non-tumor hepatic cell lines.RESULTS:Immunohistochemical staining of liver biopsy specimens from HCC patients showed that the YKL-40 protein expression in tumor tissue was higher than that in adjacent normal tissues.ELISA revealed that the YKL-40 serum level in the HCC group was significantly higher than that in the IHC group,but not significantly different from that in the cirrhosis group.Real-time PCR showed that YKL-40 mRNA levels in HCC cell lines were significantly higher than those in nontumor hepatic cells.CONCLUSIONS:YKL-40 is highly expressed in HCC at the molecular,cellular and tissue levels.However,it may not serve as a serum biomarker for HCC because measurement of the serum YKL-40 level cannot distinguish HCC from cirrhosis.