IDO1 and neoplasm: For example, an important member of the B7 transmembrane protein family (B7-H4), the Indoleamine 2,3-Dioxygenase 1 (IDO1) coding gene, the Lymphocyte Activating 3 (LAG3), the Cluster of Differentiation 48 antigen (CD48), and TNF Receptor Superfamily Member 9 (TNFRSF9) had a significant positive correlation with dMMR, a high tumor mutational burden.