Cartilage Oligomeric Matrix Protein (COMP) Correlates with Disease Progression, Selected Immune Checkpoint Molecules and SIGLEC9 in Colorectal Cancer.

Cartilage oligomeric matrix protein (COMP) influences extracellular matrix remodeling. We investigated its clinical, prognostic, and immunomodulatory significance in colorectal cancer (CRC). COMP was quantified via ELISA in 107 paired CRC and normal tissues. Expression was correlated with clinicopathological features, mutational profiles, microsatellite instability (MSI), tumor-infiltrating lymphocytes (TILs), immune checkpoints, and multiplex cytokine networks. For transcriptomic validation, the FieldEffectCrc dataset was used for Gene Set Enrichment Analysis (GSEA), and The Cancer Genome Atlas (TCGA) CRC cohort for survival analysis. COMP was significantly upregulated in CRC tissues (p < 0.001) and correlated with advanced T, N, and overall pathological stages (all p < 0.05, tau = 0.18, 0.21, and 0.23, respectively). High COMP expression was linked to restricted immune infiltration (reduced stromal TILs, p < 0.05, tau = -0.23), elevated levels in microsatellite stable (MSS) compared to MSI tumors (p < 0.01), and correlated positively with immune exhaustion markers (T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), galectin-9 (GAL9), sialic acid-binding Ig-like lectin 9 (SIGLEC9)). Transcriptomic data linked high COMP to worse disease-specific and progression-free survival, and enrichment in pro-tumorigenic pathways (epithelial-to-mesenchymal transition, angiogenesis, IL-6 signaling). COMP upregulation defines an immunosuppressive microenvironment in CRC, particularly in MSS tumors. It represents an important prognostic biomarker and potential therapeutic target for overcoming immunotherapy resistance.