TNFRSF9 and cancer: In view of the importance of immune checkpoints in cancer treatment, the expression of 13 checkpoint genes (BTLA, TNFRSF9, ICOS, PDCD1, TIGIT, CTLA4, LAG3, CD274, TNFRSF4, HAVCR2, SIRPA, CD47 and VTCN1) were compared.