High KIF18A expression correlates with unfavorable prognosis in primary hepatocellular carcinoma

This study aimed to investigate KIF18A expression in hepatocellular carcinoma (HCC) and to determine the possibility of KIF18A expression being a biomarker in HCC diagnosis or being an independent predictor of disease-free survival (DFS) and overall survival (OS) in HCC patients underwent surgical resection. KIF18AmRNA was detected in 216 cases of HCC tissues by quantitative real-time PCR (qRT-PCR) and in 20 cases of HCC tissues by semi-quantitative RT-PCR. KIF18A protein was determined in 32 cases of HCC tissues by immunohistochemistry (IHC). The survival probability was analyzed by Kaplan-Meier method, and survival curves between groups were obtained by using the log-rank test. Independent predictors associated with DFS were analyzed with Stepwise Cox proportional hazard models. High KIF18A mRNA level was detected in 154 out of 216 (71.3%) cases of HCC. The positive rate of KIF18A expression was significantly higher in liver cancer tissues than that in adjacent normal liver tissues (ANLT) from HCC patients [65.6% (21 of 32) vs. 25.0% (8 of 32), P=0.001]. The KIF18A expression level had positive relevance to the alpha-fetoprotein (AFP) (≥ 200 ng/ml), tumor size (≥ 5 cm), clinical tumor-node-metastasis (TNM) stage and portal vein tumor thrombus (PVTT) in HCC (all P <0.05). A survival analysis indicated that HCC patients with higher KIF18A expression had a significantly shorter DFS and OS after resection. A multivariate analysis suggested that KIF18A upregualtion was an independent factor for DFS [hazard risk (HR)=1.602; 95% confidence interval (CI), 1.029-2.579; P=0.031] and OS (HR=1.682; 95% CI, 1.089-2.600; P=0.019). KIF18A might be a biomarker for HCC diagnosis and an independent predictor of DFS and OS after surgical resection.