The clinical and prognostic implications of pluripotent stem cell gene expression in hepatocellular carcinoma

Recently, growing evidence has demonstrated that aberrant expression of pluripotent stem cell-related genes may confer primitive and aggressive traits and be associated with unfavorable clinical outcomes in certain solid cancers. However, the role of pluripotent stem cell gene expression in hepatocellular carcinoma (HCC) remains unexplored. We evaluated the expression of the pluri potent stem cell genes Oct4, Sox2 and Klf4, as well as that of the c-Myc, Nanog and Lin28 genes in HCC samples and corresponding adjacent non-tumor liver samples obtained from 57 patients using quantitative real-time reverse transcription-PCR (qRT-PCR). The results revealed that six pluripotent stem cell gene expression levels were upregulated in the tumor tissues compared with the corresponding adjacent non-tumor liver tissues. In HCC tissues, aberrant expression of Sox2 and Lin28 was associated with a large tumor size (P=0.02 and P=0.03, respectively), while increased expression levels of c-Myc (P=0.01) were correlated with vascular invasion. Moreover, high Klf4 expression levels were associated with aggressive tumor behaviors in terms of vascular invasion (P=0.02) and poor tumor differentiation (P=0.03). Survival analysis revealed that Klf4 expression was independently associated with overall survival [OS; hazard ratio (HR), 8.61; 95% confidential interval (CI), 2.7-27.5; P<0.001] and recurrence-free survival (RFS; HR, 3.96; 95% CI, 1.3-11.6; P=0.01). In conclusion, pluripotent stem cell genes are associated with HCC progression and a poor prognosis. The development of therapeutic strategies, including adjuvant therapy, that take cancer stem cell (CSC)-related markers into consideration is likely to be a key factor in further improvements of the prognosis of HCC patients undergoing curative liver resection.