To establish a cell line with a permanent suppression of hLRH-1 in this study, a stable RNAi vector (pSineohLRH-1) targeting hLRH-1 was constructed and introduced into hepatocellular carcinoma cell, BEL-7402. By semiquantitative RT-PCR analysis, the expression of hLRH-1 in BEL-7402 cells carrying pSineohLRH-1 was shown to be significantly suppressed by up to approximately 60%. In addition, microarray analysis was carried out to assess the extent of altered gene expression in BEL-7402 cells with stable knockdown of hLRH-1. Direct comparison of gene-expression profiles of more than 18,000 genes showed that 405 of the expressed genes in hLRH-1-knockdown cells differed dramatically in expression levels from those in controls, which suggested the even extensive biological functions of hLRH-1. Interestingly, among those differentially expressed genes, some are cancer-associated such as Gadd45beta and PTEN, and their expressions were further validated. Although the identification of the exact relationship between these genes and hLRH-1 awaits intensive investigation, the findings of this study provide new insights into the mechanism by which hLRH-1 is involved in tumorigenesis.