Bioinformatics Analysis of Apolipoprotein H Demonstrates Its Potential as a Prognostic Biomarker in Kidney Renal Clear Cell Carcinoma

Objectives: This study aimed to systematically reveal the clinical value of APOH in KIRC. Methods: The expression of APOH and its methylation level in KIRC were explored. Also, the prognostic value of APOH was evaluated. In addition, the correlation of APOH and immune infiltrates in KIRC was analyzed. Finally, enrichment analysis was performed to predict the APOH-associated pathways in KIRC. Results: Compared with the normal group, APOH was down-regulated in KIRC both in mRNA and protein levels. The APOH expression was related to several phenotypes of KIRC patients. Kaplan-Meier analysis showed that APOH high expression correlated with shorter OS, PFI, and DSS time. Cox regression only indicated the independent prognostic impact of APOH for PFI. ROC curve showed the better prediction performance of APOH for PFI and nomogram further revealed its contribution to survival probability. Additionally, a negative correlation between APOH expression and methylation was observed, and APOH methylation did not influence the prognosis of patients. In addition, both expression and methylation of APOH were related to immune infiltrates, suggesting the importance of immune infiltrates in KIRC. Finally, the KEGG and GSEA analyses indicated a positive relationship of APOH with Complement and coagulation cascades pathways in KIRC. Conclusions: APOH was closely related to the prognosis of KIRC patients and might be involved in the Complement and coagulation cascades pathway, implying the involvement of APOH in tumorigenesis and metastasis of KIRC.