Evaluating IL22RA1 expression as a predictive indicator in human colon cancer progression.

BACKGROUND: Colon cancer is a prevalent malignancy of the digestive tract, consistently ranking among the top three cancers globally in both incidence and mortality. Current standard treatments for colon cancer primarily include surgical resection and adjuvant chemoradiotherapy, while only a limited subset of patients derive substantial benefits from immunotherapy. Consequently, further investigations into the pathogenesis and immune microenvironment of colon cancer, along with the identification of effective therapeutic targets, are crucial for improving patient prognoses. METHODS: In this study, we utilized a multi-color immunohistochemistry (mIHC) assay to examine the expression patterns of IL22RA1, IL22, CD155, and IL22BP in a tissue microarray (TMA) comprising 90 colon cancer samples. Additionally, we assessed the immunolocalization, clinical relevance, and prognostic significance of these molecules. RESULTS: The mIHC results, supported by multispectral tissue imaging, revealed that IL22RA1 was predominantly expressed in tumor epithelial cells. Expression levels of IL22RA1, CD155, and IL22BP in colon cancer tissues were markedly higher than those in adjacent normal tissues, with statistically significant differences (t = 6.05, 9.53, 3.91, all P < 0.001). Analysis of TMA and publicly available databases demonstrated that patients with low IL22RA1 expression exhibited significantly improved overall survival (OS) compared to those with high IL22RA1 expression. Furthermore, patients characterized by high co-expression of IL22RA1 and IL22 (IL22RA1(high)IL22(high)) had notably poorer OS compared to others. Similar trends were observed for patients with IL22RA1(high)CD155(high) or IL22(high)CD155(high) expression patterns, all of whom experienced significantly worse OS. Conversely, patients with low IL22RA1 expression and high IL22BP expression (IL22RA1(low)IL22BP(high)) exhibited substantially better OS than those with IL22RA1(high)IL22BP(low) (all P < 0.05). Correlation analysis highlighted a strong positive relationship between the infiltration levels of IL22RA1(+)CK(+) cells and CD155(+)CK(+) cells in tumor tissues (r = 0.55, P < 0.001). Cox multivariate regression analysis identified high IL22RA1 expression in tumor cells as an independent risk factor for poor prognosis (HR = 2.726, 95% CI: 1.190-6.242, P = 0.018). Analysis of immune cell infiltration revealed that tumors with elevated IL22RA1 expression exhibited significantly diminished infiltration of several T cell subsets, particularly central memory CD8⁺ T cells and memory CD4⁺ T cells, relative to tumors with lower expression levels. CONCLUSIONS: Elevated IL22RA1 expression in colon cancer tissues was associated with worse patient outcomes, potentially driven by its interaction with IL22 and CD155 in tumorigenesis. These findings underscored the pivotal role of IL22RA1 as a prognostic biomarker and highlighted its potential as a promising immunotherapeutic target for colon cancer.