Olink Target 96 Immuno-Oncology Panel

Colorectal cancer (CRC) is showing an increasing incidence and mortality rate in China, with approximately 555,000 new cases and 286,000 deaths reported in 2020. Early symptoms of CRC are often not apparent, and most patients are diagnosed at advanced stages. Early detection and targeted therapy are crucial for improving survival rates. The study aims to identify non-invasive biomarkers for CRC by detecting changes in tumor immune-related circulating proteins in peripheral blood.

Ninety-two proteins were detected in the serum of CRC patients' peripheral blood, and 49 differentially expressed proteins were identified, of which 42 were upregulated and 7 were downregulated. GO analysis revealed that genes with high expression levels in CRC were mainly enriched in cell adhesion and lymphocyte proliferation signaling pathways. KEGG enrichment analysis showed that these genes were primarily enriched in cytokine-cytokine receptor interactions and the PI3K-AKT signaling pathway.

Figure 1. Differential protein expression heat map. (Wan, Y., et al., 2024)

The differential proteins identified were used to predict a signature model, which revealed that a signature composed of 6 proteins (IL7, CXCL12, IL10, IL15, CXCL1, and MCP-3) could effectively differentiate CRC from control samples. The performance of the signature model was evaluated using Receiver Operating Characteristic (ROC) analysis, showing an AUC of 0.9224 in the training set and 0.8992 in the total set. The performance surpassed that of the classic clinical markers CEA and CA-19-9.

Figure 2. Prediction result of protein signature model. (Balzer, M. S., et al., 2024)

Subsequently, the best protein model identified was validated in CRC and control samples using ELISA technology, with IL7, CXCL12, IL10, and CXCL1 showing consistent results with the Olink findings. Impedance analysis was used to measure the absolute counts of immune cells (lymphocytes, monocytes, neutrophils, eosinophils, and basophils) in the peripheral blood of CRC patients. The results showed that the absolute count of lymphocytes in the CRC group was lower than that in the control group, while the absolute count of monocytes in CRC patients was significantly higher than in healthy controls. CXCL1 levels were positively correlated with the absolute count of basophils, and IL10 levels were positively correlated with the absolute count of neutrophils.