Clinicopathological Analysis and Prognostic Assessment of Transcobalamin I (TCN1) in Patients with Colorectal Tumors

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignancies worldwide. Overall survival (OS) of patients is largely dependent on disease stage at diagnosis and/or surgical resection. TCN1 mainly encodes the vitamin B12 transporter, transcobalamin. Early studies show that TCN1 is a marker of CRC progression, but the impact of TCN1 on survival is unclear. MATERIAL/METHODS: We reviewed and analyzed colorectal tumor records, summarized the clinicopathological data, performed immunohistochemical detection of TCN1 again, and semi-quantitatively analyzed protein expression in tumor tissue, non-tumor tissue, and lymph nodes. We followed up patients for 5-year survival. RESULTS: Of 123 patients, 60 (48.7%) had a strong TCN1 immunohistochemical reaction, 36 (29.3%) had a moderate immune response, and 27 (22.0%) had weak expression. The level of immunohistochemical reactivity of TCN1 was correlated with the degree of histological differentiation (H (2.92)=4.976; P=0.083). Survival analysis showed that OS in patients with low TCN1 expression was significantly longer than that in the medium and high TCN1 expression groups (P=0.045). Five-year OS in patients with low, medium, and high TCN1 expression was 88.9%, 50.0%, and 40.0%, respectively. In univariate analysis, TCN1 immune expression was significantly correlated with the 5-year survival rate. CONCLUSIONS: Although independent risk factors affecting survival of patients with CRC are age, serum CA125, CA19-9, lymph node metastasis, and nerve invasion, negative factors affecting overall 5-year survival in TCN1 should not be ignored, because its high expression suggests a worse clinical prognosis.