CD274 and neoplasm: In a large (n = 155) CTCL/PTCL series [21], PD-L1 was expressed by lymphoma cells in 27% of CTCL and 15% of PTCL, but PD-L1 expression within the tumor microenvironment was more common, being observed in 73% and 39% of CTCL and PTCL cases, respectively.