Express And Clinical Significance Of Hepatic Stem/Progenitor Cells Marker ABCG2in Hepatocellular Carcinoma

Objective：primary hepatic carcinoma（PHC) is a common malignancy.Pathogenesis is still unclear for PHC.In recent years,the theory was put forwardthat human liver cancer originated in the hepatic stem/progenitor cells.ATPbinding cassette transporter protein G family member2(ABCG2) is selected asthe stem cell marker.The aim of the present study is to investigate the expressionof ABCG2in human hepatocellular carcinoma and matching tumor-adjacent andnormal liver specimens, and its association with clinicopathological features andprognostic significance.Methods：60cases of HCC specimens and matching tumor-adjacent and7cases of normal liver tissues were collected from patients operated inDepartment of Hepatobiliary Surgery, the Affiliated Hospital of Guilin MedicalCollege,during May2009--July2012.Including42cases of males and18cases of females,aged30to68years,a median age of50.3years.27cases of tumordiameter≥5cm,27cases of tumor diameter <5cm;19cases of serum AFP(-),23cases of multiple tumors;29cases of poorly differentiated,31cases of welldifferentiated;28cases of lymph node metastasis.The specimens were fixed in10%formalin and routinely embedded in Paraffin.Patients and their familiesagreed to acquire specimens. Patients have no preoperative radiotherapy andchemotherapy,and pathologically diagnosed HCC.ImmunohistochemistryEnVision methods were utilized to detect the expression of ABCG2inspecimens of HCC and matching tumor-adjacent and normal liver tissues.To analyze immunohistochemical results,and its association with clinicpathological features and prognostic significance.Results：positive expression is mainly locate in the cancer cellintracytoplasm of HCC tissues,to show diffusive distribution of borwn-granulo;ABCG2had been expressed in biliary epithelial cells and Heringtubules of tumor-adjacent tissues.The expression of ABCG2in HCC tissue ishigher than in tumor-adjacent tissue.In normal liver tissue, the expression ofABCG2were negative.The positive rate of ABCG2protein in hepatocellularcarcinoma were60.1%(37/60),and were21.6%(13/60) in tumor-adjacenttissues.There is a significant difference between the expression rate of ABCG2in HCC tissues and that in adjacent cirrhotic tissue(χ2=15.931,P<0.05).The expression of ABCG2protein was not concerned with age，gender or tumor sizes or number,but was significantly correlated with serum alpha-fetoprotein，Poorly-differentiation,and lymphatic metastasis(P<0.05).Additionally，Kaplan-Meier survival analysis showed that HCC patients with positive ABCG2expression had a worse overall survival and disease-free survival compared withthose with negative ABCG2expression (P<0.001, respectively).Conclusion：Expression of ABCG2protein is abnormal in hepatocellularcarcinoma,and ABCG2may be a potential marker of liver stem cells.ABCG2may be served as a valuable prognostic biomarker for HCC patients.