Background: Oct4 and Nanog are two major transcription factors related to the stem cell self-renewal and differentiation. The aim of this study was to evaluate the correlation between these two stemness markers with recurrence, metastasis, and prognosis of hepatocellular carcinoma (HCC).
Methods: Expression of Oct4 and Nanog was evaluated by immunohistochemistry in a random cohort of 228 HCC patients (cohort A), predominantly hepatitis B related, and validated in another independent cohort of 95 patients (cohort B). Survival analysis was performed by univariate and multivariate analyses. Oct4 and Nanog expression levels in 5 HCC cell lines with different metastatic potential were detected by Western blot assay and quantitative real-time PCR assay.
Results: In tissue microarrays, coexpression of Oct4 and Nanog was dramatically associated with big tumor size (P = .001) and vascular invasion (P = .02) and was an independent predictor of postoperative recurrence (hazard ratio [HR] = 1.57, 95 % confidence interval [95 % CI] 1.21-2.04, P = .01) and poor prognosis (HR = 2.20, 95 % CI 1.71-2.88, P < .001). This association was further validated in patients in cohort B. Importantly, this correlation remained significant in patients with early-stage HCC or alpha-fetoprotein (AFP) negative HCC. In addition, expression of Oct4 and Nanog increased in a concordant manner with the increase of metastatic potential in human HCC cell lines.
Conclusions: Coexpression of stemness markers Oct4 and Nanog in HCC indicated the aggressive tumor behaviors and predicted a worse clinical outcome, which may be a useful biomarker to identify patients at high risk of postoperative recurrence.