CD274 and adult T-cell leukemia/lymphoma: Likewise, cases of HTLV1-associated leukemia and lymphoma of adults (ATLL) have been shown to overexpress PD-L1 at the surface of their tumor or ME stromal cells [54, 91, 92], and the presence of PD-L1+ tumor cells, together with the lack of PD-L1+ ME cells, has been correlated with a poor prognosis in ATLL patients [92].