CD28 and bladder transitional cell carcinoma: The expression of THEM6 was negatively correlated with most immunostimulators in BLCA, such as TNFSF9, TNFRSF18, CD28, CD276, TNFRSF4, TNFRSF17, and CD4. In the THEM6-high expression group, there was a downregulation in most of the MHC molecules, which represent antigen presentation and processing ability.