COA4 and polyarteritis nodosa: Pan‐cancer analysis using the TIMER2.0 database revealed significantly elevated COA4 expression in multiple malignancies—including LUAD, pancreatic adenocarcinoma (PAAD), colon adenocarcinoma (COAD), breast cancer (BRCA), hepatocellular carcinoma (HCC), and clear cell renal cell carcinoma (ccRCC)—compared to normal tissues (Figure S2A, Supporting Information), suggesting an oncogenic role for COA4.