Membrane bound Peroxiredoxin-1 serves as a biomarker for in vivo detection of sessile serrated adenomas.

Aim Sessile serrated adenomas (SSAs) are pre-malignant lesions driven by the BRAFV600E mutation to give rise to colorectal cancers (CRCs). They are often missed during white light colonoscopy because of their subtle appearance. Previously, a fluorescently-labeled 7mer peptide KCCFPAQ was shown to detect SSAs in vivo. We aim to identify the target of this peptide. Results Peroxiredoxin-1 (Prdx1) was identified as the binding partner of the peptide ligand. In vitro binding assays and immunofluorescence staining of human colon specimens ex vivo supported this result. Prdx1 was overexpressed on the membrane of cells with the BRAFV600E mutation, and this effect was dependent on oxidative stress. RKO cells harboring the BRAFV600E mutation and human SSA specimens showed higher oxidative stress as well as elevated levels of Prdx1 on the cell membrane. Innovation and Conclusions: These results suggest that Prdx1 is overexpressed on the cell surface in the presence of oxidative stress, and can serve as an imaging biomarker for in vivo detection of SSAs.