Gene expression profiles of different subpopulations of hepatocellular carcinoma

To demonstrate CD133+CD44+ and CD133+CD44- subpopulations of hepatocellular carcinoma as distinct subgroups, we have employed whole genome microarray expression profiling as a discovery platform to reveal the gene profiles of different subgroups and identify genes responsible for the enhanced metastatic potentials of CD133+CD44+ tumor cells. CD133+CD44+ and CD133+CD44- tumor cells were isolated from three human metastatic hepatocellular carcinoma specimens. A 76-gene consensus signature was identified that distinguished between CD133+CD44+ and CD133+CD44- subgroups. CD133+CD44+ and CD133+CD44- subgroups from different patients were well clustered as two distinct classes according to this signature, and many genes in this signature were reported involved in tumor metastasis. Expression of four genes (CCL4, DKK3, CCR5 and MMP12) from this signature was confirmed in another three metastatic HCC specimens by real-time PCR. CD133+CD44+ and CD133+CD44- subpopulations of hepatocellular carcinoma were isolated from three metastatic hepatocellular carcinoma specimens by flow cytometry. A total of 30K to 50K cells for each subgroup was obtained for each microarray.