Abstract
BACKGROUND: Colorectal cancer (CRC) is a common tumor of the digestive system. In recent years, CRC has had the fourth highest incidence and second highest mortality rate among tumors worldwide. Therefore, it is important to identify new molecular markers, and examine their relationship with the clinicopathological features and prognosis of CRC patients. This study examined the correlation between the expression levels of the tropomyosin receptor kinase C (TRKC) and neurotrophic factor-3 (NT-3) proteins, and the clinicopathological features and prognosis of CRC patients. METHODS: In total, 141 paraffin-embedded specimens from patients who had undergone radical surgical resection for CRC were analyzed. All CRC diagnoses were confirmed by pathological examination. Corresponding adjacent normal tissues served as controls. Immunohistochemical staining was employed to assess the expression of the TRKC and NT-3 proteins in both the CRC and adjacent normal tissues. A subsequent statistical analysis was conducted to explore the associations between the expression levels of these proteins, and the clinicopathological features and prognostic outcomes of CRC patients. RESULTS: The expression level of TRKC was significantly higher in the CRC tissues than the adjacent normal tissues, while the expression level of NT-3 was significantly lower in the CRC tissues than the adjacent normal tissues, and the observed differences were statistically significant (P<0.001). Notably, TRKC expression was significantly correlated with the tumor site (P<0.05), lymph node metastasis (P<0.05), tumor node metastasis (TNM) stage (P<0.01), serum carcinoembryonic antigen (CEA) level (P<0.01), and serum carbohydrate antigen 19-9 (CA199) level (P<0.05). The patients with positive TRKC had significantly shorter overall survival (OS) and progression-free survival (PFS) times than those with negative TRKC expression (P<0.001). Further, NT-3 expression was significantly associated with lymph node metastasis (P<0.05), distant metastasis (P<0.05), TNM stage (P<0.05), and serum CEA level (P<0.05). The patients with positive NT-3 expression had prolonged OS and PFS compared to those with negative NT-3 expression (P<0.01). The Cox proportional hazards regression model revealed that TRKC expression had a hazard ratio (HR) of 2.679 (P<0.01), while NT-3 expression had a HR of 0.433 (P<0.05). CONCLUSIONS: We found that the TRKC and NT-3 proteins were closely associated with the occurrence, metastasis, invasion, and tumor marker levels of CRC, and can be used as independent predictors of prognosis in patients with CRC. TRKC mainly indicates a poor prognosis in CRC, while NT-3 indicates a good prognosis.