Prohaptoglobin is a possible prognostic biomarker for colorectal cancer

Fucosylated haptoglobin is a novel glycan biomarker for colorectal and other cancers, while the significance of its precursor, prohaptoglobin (proHp), remains to be elucidated. In this study, we investigated whether proHp can be a colorectal cancer (CRC) biomarker and the biological functions of proHp in CRC using 10-7G, a monoclonal antibody recently developed in our laboratory.

Serum proHp level in 74 patients with CRC was semi-quantified by western blotting, and 5-year recurrence-free survival and overall survival were analyzed for groups stratified by proHp status (high vs. low). We also performed immunohistochemical analyses of 17 CRC tissue sections using 10-7G mAb. The biological functions of proHp were evaluated by overexpressing proHp in CRC cell lines.

Serum proHp correlated with the clinical stage and poorer prognosis of CRC. In the primary CRC sections, immune cells were stained positive for 10-7G in ∼50% of the cases. Overexpression of proHp in HCT116 human CRC cells induced epithelial-mesenchymal transition-like changes and promoted cell migration in CRC cells.

We provide evidence for the first time that proHp has potential as a prognostic biomarker for CRC and demonstrated specific biological activities of proHp.