N‑Glycoprotein Analysis Discovers New Up-Regulated Glycoproteins in Colorectal Cancer Tissue

Colorectal
cancer is one of the leading causes of death due to
cancer worldwide. Therefore, the identification of high-specificity
and -sensitivity biomarkers for the early detection of colorectal
cancer is urgently needed. Post-translational modifications, such
as glycosylation, are known to play an important role in cancer progression.
In the present work, we used a quantitative proteomic technique based
on 18O stable isotope labeling to identify differentially
expressed N-linked glycoproteins in colorectal cancer tissue samples
compared with healthy colorectal tissue from 19 patients undergoing
colorectal cancer surgery. We identified 54 up-regulated glycoproteins
in colorectal cancer samples, therefore potentially involved in the
biological processes of tumorigenesis. In particular, nine of these
(PLOD2, DPEP1, SE1L1, CD82, PAR1, PLOD3, S12A2, LAMP3, OLFM4) were
found to be up-regulated in the great majority of the cohort, and,
interestingly, the association with colorectal cancer of four (PLOD2,
S12A2, PLOD3, CD82) has not been hitherto described.