Aberrant expression of nuclear KPNA2 is correlated with early recurrence and poor prognosis in patients with small hepatocellular carcinoma after hepatectomy

Karyopherin α2 (KPNA2) functions as an adaptor that transports several proteins to the nucleus. Emerging evidence suggests that KPNA2 plays a crucial role in oncogenesis and early recurrence. In the present study, we evaluated the expression pattern of KPNA2 in 221 hepatocellular carcinoma (HCC) specimens and matching adjacent, non-tumorous tissues (NT) by immunohistochemical assays. We found that nuclear KPNA2 expression was significantly upregulated (30.3 %, 67/221) in HCC tissues; however, no nuclear expression of KPNA2 in NT tissues was observed. A correlation analysis demonstrated that nuclear KPNA2 expression was positively associated with serum AFP level, tumor differentiation, vascular invasion, BCLC stage and early recurrence (all p < 0.05). Nuclear KPNA2 expression was associated with a poor prognosis in HCC patients. Univariate and multivariate analyses demonstrated that KPNA2 was an independent prognostic factor for both overall survival (p < 0.001) and time to recurrence (p < 0.001) in HCC patients. Furthermore, in a validation cohort, nuclear expression of KPNA2 was observed in 16 of 47 (34.0 %) small hepatocellular carcinoma patients. Importantly, the risk of recurrence associated with nuclear KPNA2 expression (9/16, 56.2 %) was significantly higher than the risk associated with an absence of nuclear KPNA2 expression (6/31, 19.3 %; p = 0.01). Our results demonstrate that nuclear KPNA2 expression is a poor prognostic biomarker for HCC, especially for early-stage HCC.