Pattern of Melanotransferrin Expression in Human Colorectal Tissues: An Immunohistochemical Study on Potential Clinical Application

Abstract

Background: Our previous liquid chromatography-tandem mass spectrometry (LC-MS/MS) study on colorectal cancer proteome resulted in identification of 10,000 differentially expressed proteins. We observed a significantly changed expression of 25% of all identified proteins between patient and matched adjacent normal mucosa, carcinoma and colorectal adenoma, including melanotransferrin. Herein, we consider this protein as a potential biomarker of colorectal cancer.

Materials and methods: Immunohistochemical detection of melanotransferrin was carried-out to localize its expression pattern within the colorectal tissues by tissue microarray. The diagnostic utility of melanotransferrin was evaluated in patient serum by enzyme-linked immunosorbent assay (ELISA).

Results: Strong melanotransferrin expression was found to be related to clinicopathological characteristics, lymph node involvement (p=0.008), tumor localization in colon (p=0.001), presence of mucin (p<0.013) and increasing tumor grade (p<0.001). Melanotransferrin level in serum from patients with colorectal cancer was significantly higher than that in healthy controls (p<0.001).

Conclusion: We provide novel evidence that melanotransferrin may be involved in transformation from benign tumor to malignancy and is a marker of an invasive tumor phenotype.

Keywords: Melanotransferrin; adenoma–carcinoma sequence; colorectal carcinoma; pathogenesis; poorly differentiated adenocarcinoma; tumorigenesis.