Nemo-like kinase expression predicts poor survival in colorectal cancer

Nemo-like kinase (NLK), a serine/threonine protein kinase, was previously reported to be associated with tumor proliferation and invasion. The present study aimed to evaluate whether NLK participates in the tumorigenesis and progression of colorectal cancer (CRC). NLK expression was examined using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis in 50 paired CRC tissues as well as immunohistochemical analysis of 406 cases of primary CRC tissues and paired non-cancerous tissues. Correlations between NLK expression, the clinicopathological features of CRC patients and clinical outcome were then analyzed. NLK expression was found to be significantly higher in CRC tissues as well as associated with the depth of tumor invasion, lymph node metastasis, distant metastasis, histological differentiation, vascular invasion and advanced tumor stage. Patients with NLK-positive tumors demonstrated higher rates of recurrence and mortality than patients with NLK-negative tumors. Multivariate analyses revealed that NLK expression was an independent factor for overall survival [hazard ratio (HR)=0.035; 95% confidence interval (CI)=0.02-0.19; P<0.001] and disease-free survival (HR=0.033; 95% CI=0.007-0.09; P<0.001) in CRC patients. In conclusion, the results of the present study indicated that NLK may serve as a novel biomarker for tumor recurrence and survival for CRC patients.