OBJECTIVETo study human hepatocarcinoma stem cell markers.

METHODSTumor tissue samples were obtained from 8 patients with hepatic cellular cancer undergoing surgical tumor resection and the tumor cells were cultured with primary tissue culture in vitro. The cell subpopulations with each marker were isolated from the tumor cells by immunopanning using oval cell markers (CD34, c-kit, Thy-1, CK7, CK19, CK14). The cells of each phenotype were injected into nude mice to measure their ability of tumor formation and the tumor mass was weighed one month after implantation. The tumorigenic subpopulations of the cells were injected into the nude mice again in 1/4 or 1/10 of their original densities to further analyze their ability of tumor formation.

RESULTSAmong all the cell subpopulations, those positive for CD34, c-kit and CK7, respectively, showed marked difference from the negative cells in their ability of proliferation and tumor formation. The CD34(-), c-kit(+) and CK7(+) subpopulations of the cells exhibited strong capacity of tumor formation even in only 1/4 or 1/10 of their original density.

CONCLUSIONSThere are heterogeneous subpopulations within human hepatocarcinoma with observable difference in tumor formation ability. The strong tumor formation ability of CD34(-), c-kit(+) and CK7(+) subpopulation of the cells suggests that CD34(-), c-kit(+) and CK7(+) represent part of the surface markers of hepatocarcinoma stem cells.