Identification of Potential Urinary Protein Biomarkers in Colorectal Cancer: A Pilot Study Using a Proteomic Approach

Colorectal cancer (CRC) is among the most diagnosed malignancies worldwide, and it is also the second leading cause of cancer-related deaths. Despite recent progress in screening programs, noninvasive accurate biomarkers are still needed in the CRC field. In this study, we evaluated and compared the urinary proteomic profiles of patients with colorectal adenocarcinoma and patients without cancer, aiming to identify potential biomarker proteins. Urine samples were collected from 9 patients with CRC and 9 patients with normal colonoscopy results. Mass spectrometry (label-free LC‒MS/MS) was used to characterize the proteomic profile of the groups. Ten proteins that were differentially regulated were identified between patients in the experimental group and in the control group, with statistical significance with a p value ≤ 0.05. The only protein that presented upregulation in the CRC group was beta-2-microglobulin (B2M). Subsequent studies are needed to evaluate patients through different analysis approaches to independently verify and validate these biomarker candidates in a larger cohort sample.