CCL21 and neoplasm: Next, we performed PPI network analysis and found 10 microenvironment-associated hub genes, including GPR55, CCR4, C3, CCL21, CCR7, CCL19, and CXCL13, which have been reported to promote proliferation, angiogenesis, migration, and invasiveness by altering the tumor microenvironment 41-44, and identified CCR4, GNG8 and CXCL13 were associated with prognosis of ccRCC patients.