It was found that CD8 tumor-infiltrating lymphocytes (TILs) upregulate costimulatory molecules of the TNF-R family, especially 4-1BB and, to a lesser extent, CD134/OX40, and lead to a loss of CD27 and CD28 expression during initial TCR stimulation [18, 22]. The gene discussed is TNFRSF9; the disease is neoplasm.