| It is suggested that the genesis of tumor may be a result of the malignant proliferation of the cancer stem cells(CSCs) in the latest theory about CSCs. CSCs are rare fractions of tumor cells that can immortally differentiate .These cells possess self-renew and differentiation potential and can differentiate into tumor cells of different differentiation level. CSC is a root of tumor recurrence and metastasis, and plays an significant role in tumor genesis and maintenance. The existence of CSCs has been verified in a variety of tumors, including Myeloid Leukemia, Breast cancer, Glioma, Prostatic carcinoma, Colo carcinoma. According to the hypothesis about CSCs, CSCs may share some similar properties with normal stem cells, and they dominate the tumor genesis and progress. Therefore, trying to isolate and identify the CSCs will be a fundamental work for interpreting the mechanisms of tumor genesis, recurrence and metastasis, which can also provide a totally new strategy for tumor therapy.Hepatocellular carcinoma (HCC) is one of the most common tumors in our country. The recurrence and metastasis of HCC is the main cause that leads to the death of patients. Studies on the mechanisms of HCC genesis show that hepatic oval cells, which possess the characteristics of liver progenitor cells, involves in the process of HCC genesis. In addition, the heterogeneity in HCC tissue suggests that cells in tumor tissue does not play an equal role in cancer genesis and progress, and there must be some special cells with specific phenotype, which may be relatively more important in tumor genesis. Isolation of these special cells and attempting to identify whether they possess the characteristics of normal stem cells or not will prompte the interpretation of the mechanisms of HCC genesis.A variety of studies show that stem cells widely involves in the process of HCC genesis and progress. Whether a specific surface molecule can be targeted or not has become a key step of stem cell studies. It has been determined that CD133+ cells isolating from tumors of different organizations possess the prosperity of CSCs. Furthermore, the reexpression of CD133 has been observed in the regeneration process of rat liver after 2/3 hepatectomy, which indicates that CD133 is closely associated with the proliferation of liver cell. Threfore, in our research we try to isolate and identificate CD133+ cells in tumor tissues, and to explore the proliferation characteristics of CD133+ subpopulations, which may provide a fundamental basis to reveal the molecular mechanisms of carcinogenesis, recurrence and metastasis of HCC, and may promote the development of new strategies for HCC treatment.Object:1.To detect the expression of CD133 in hepatocellular carcinoma tissues and to investigate the correlation between CD133 and clinical features and prognosis of the patients.2.To detect the biologic behaviors of the CD133+ cells of HCC tissues in vitro and vivo. Furthermore, to investigate the proliferation properties of the CD133+ subpopulation in HCC cell lines.Mothod:1 . Envision immunohistochemical staining is adopted to detect the expression of CD133 and Ki-67 in 52 cases of HCC, as well as 6 cases of normal liver specimens. Furthermore, the correlation between CD133 expression as well as Ki-67 expression and clinicopathological index as well as survival rate after hepatectomy is analysed.2 . Fluorescence-activated cell sorting(FACS) is used to detect the expression of CD133 in Huh-7 cell line.3.CD133+ and CD133- cells of HCC and Huh-7 cell line are cultured in vitro, and the proliferation and differentiation of these cells are observed. Furthermore, a cell implantation experiments is done to test the tumorigenicity of these cells.Result:1.The average staining intensity of CD133 expression of 52 HCC is 1.07±0.32, and the positive expression rate of Ki-67 in HCC is 57.7%.In contrast, the positive expression of CD133 is not observed in normal liver tissue, neither the positive expression of Ki-67;2.Both the CD133 expression and the Ki-67 expression are significantly correlated with the Pathological grades and the clinical stages(P<0.05), but they are not correlated with the age,gender and tumor size(P>0.05). 3.The follow-up medical records of 32 HCC reveals that the 5-year survival time and the median survival time of those patients whose tumor tissue are CD133+ are respectively 28.7% and 34.2 months, as that of those patients whose tumor tissue are CD133—are respectively 44.8% and 45.4 months.4.FACS results show that the CD133 positive expression rate of Huh-7 cell line is 62.3%. Compared with CD133- cells, CD133+ cells demonstrated better proliferation capacity.5.The tumorigenicity of the CD133+ subpopulation cells in nude mice is significantly better than CD133- cells.6.CD133+ subpopulation cells has a better differentiation capacity in vitro, than CD133- cells.Conclusion:1.CD133+ cells exist in a large number in clinical specimens of HCC.2.CD133 and Ki67 expression level is higher in those HCC tissue which is more malignant and at later clinical stage, and that might effect the prognosis of HCC patients, which supports the hypothesis about CSCs.3.CD133+ subpopulation cells stronger capacity of proliferation, differentiation and tumorigenicity, which show that CD133+ subpopulation cells possess the characteristics of liver CSCs.
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