TNFRSF4 and undifferentiated pleomorphic sarcoma: A comparative transcriptomic study on myxoid liposarcoma vs. undifferentiated pleomorphic sarcoma revealed higher expression levels of the T cell markers 4-1BB/TNFRSF9 and OX40/TNFRSF4 in the latter [69]; both 4-1BB and OX40 proteins have been characterized as Treg markers and putative targets for immunotherapy, but they are are thought to define distinct immunological profiles in STS.