TNFRSF9 and neoplasm: Using this coculture model, we found that incubation with CMTM6-knockout tumor cells significantly reduced the expression of T cell activation markers (CD137 and CD69) and T cell effector cytokines (IL-2 and TNFα) compared to wild-type and CMTM6-reconstituted tumor cells (Figures 3B and S3B).