ICOS and neoplasm: Cluster 6 primarily consisted of the major histocompatibility complex molecules, such as H2-Q6, H2-Q9, and H2-Q10; cluster 9 primarily consisted of tumor immune microenvironment regulatory genes (Itgal (34), Tnfsf9 (35), Ripor2 (36), and Icos (37)); and cluster 3 primarily consisted of chemokines, such as Cxcl5, Ccl5, Cxcl1, and Cxcl3 (Figure 6B).