High NUCB2 expression level is associated with metastasis and may promote tumor progression in colorectal cancer

Nucleobindin 2 (NUCB2) is mainly expressed in the hypothalamic nuclei and has a proven role in energy homeostasis. It has also been recently reported to have a key role in tumor progression. However, the clinical significance of NUCB2 in colorectal cancer (CRC) remains unknown. In the present study, the level of NUCB2 mRNA was quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in 34 paired fresh tissues from patients with CRC. RT-qPCR was followed by immunohistochemical (IHC) staining of NUCB2 protein in tissue microarrays of 251 samples to evaluate the clinical significance of NUCB2 in CRC. The RT-qPCR indicated an upregulation of NUCB2 mRNA in CRC tissues compared with normal tissues (P=0.027). IHC staining indicated a positive association between elevated NUCB2 expression and lymph node metastasis or tumor-node-metastasis (TNM) stage. Patients with CRC and lymph node metastasis demonstrated a higher expression of NUCB2 (49.5%, 50/101) compared with those without lymph node metastasis (36.7%, 55/150; P=0.043). Furthermore, NUCB2 expression was also higher in patients with CRC and TNM stage III–IV compared with those with TNM stage I–II (50.9% vs. 35.0%; P=0.011). However, Kaplan-Meier analysis indicated no significant association between NUCB2 expression and disease-free survival of patients. Additionally, multivariate analysis did not identify the upregulation of NUCB2 as an independent prognostic predictor in patients with CRC (P=0.755). In conclusion, the present study demonstrated that upregulation of NUCB2 is significantly associated with CRC metastasis, indicating that NUCB2 may be a cancer-associated oncogene associated with the aggressive progression of CRC.