Identification of MICALL2 as a Novel Prognostic Biomarker Correlating with Inflammation and T Cell Exhaustion of Kidney Renal Clear Cell Carcinoma

Purpose: The interplay of inflammation and immunity affects all stages from tumorigenesis to progression, and even tumor response to therapy. A growing interest has been attracted from the biological function of MICALL2 to its effects on tumor progression. This study was designed to verify whether MICALL2 could be a prognostic biomarker to predict kidney renal clear cell carcinoma (KIRC) progression, inflammation, and immune infiltration within tumor microenvironment (TME).

Methods: We firstly analyzed MICALL2 expressions across 33 cancer types from the UCSC Xena database and verified its expression in KIRC through GEPIA platform and GEO datasets. The clinicopathological characteristics were further analyzed based on the median expression. Kaplan-Meier method, univariate and multivariate analyses were applied to compare survival outcomes. ESTIMATE and CIBERSORT algorithms were performed to assess immune infiltration, and a co-expression analysis was conducted to evaluate the correlation between MICALL2 and immunoregulatory genes. Enrichment analysis was finally performed to explore the biological significance of MICALL2.

Results: MICALL2 was highly expressed in 16 types of cancers compared with normal tissues. MICALL2 expression increased with advanced clinicopathological parameters and was an independent predictor for poor prognosis in KIRC. Moreover, MICALL2 closely correlated with inflammation-promoting signatures and immune infiltration including T cell exhaustion markers. Consistently, MICALL2 involved in the regulation of signaling pathways associated with tumor immunity, tumor progression, and impaired metabolic activities.

Conclusion: MICALL2 can function as a prognostic biomarker mediating inflammation, immune infiltration, and T cell exhaustion within the microenvironment of KIRC.