Recent studies have shown that the signal transducer and activator of transcription 3 (STAT3) inhibitors abrogate the expression of PD-1 ligand 1 (PD-L1; also known as CD274), and PD-1 ligand 2 (PD-L2; also known as PDCD1LG2 or CD273) on a lymphoma cell line, HKBML, in addition to an adult T-cell leukemia-lymphoma cell line, ATL-T, and a splenic lymphoma with villous lymphocyte cell line, SLVL14. Here, PDCD1LG2 is linked to leukemia.