Measurement of MMP-14 Protein, a Potential New Marker for Colorectal Cancer Detection, in Plasma Vesicles Named Exosomes

Colorectal cancer is the third most common cancer in men, and the second most common in women. Screening for colorectal cancer is based on the search for blood in the stool using fecal immunochemical test (FIT). Occult bleeding is an indication for colonoscopy. In a FIT positive population, 60% of colonoscopies are negative, 34% diagnose an adenomatous lesion, and 6% a cancer. The identification of new biological markers could reduce the number of colonoscopies performed. Cancer cells release extracellular vesicles that contain proteins, mRNAs, DNA, which they can transfer to neighbouring or distant cells. The use of exosomal proteins as novel tumor markers looks very promising. We performed a pilot study comparing the levels of different exosomal proteins in 74 subjects which was recently accepted for publication in Journal of Clinical Laboratory Analysis. Comparison of results showed that only matrix metalloproteinase 14 (MMP14) was significantly higher in patients with colorectal cancer or adenoma than in people with normal colonoscopy.

The primary objective of the current study is to determine the best cut-off value of MMP-14 for colorectal cancer screening and to evaluate the performance (Sensitivity, Specificity…) associated to this cut-off value. The secondary objective will be to determine the best cut-off value of MMP-14 for colorectal adenomas screening and to evaluate its performance.

For this purpose, 650 patients, seen for diagnostic colonoscopy following a positive FIT test, will be included in the study. After blood collection and exosome isolation, MMP-14 will be measured using a quantitative test (enzyme-linked immunosorbent assay) and the results will be associated with colonoscopy results to determine the sensitivity, specificity, positive predictive value (PPV) and net present value (NPV).