PDCD1LG2 and mediastinitis: One study identified PD-L2 expression in 78% (11/14) of primary mediastinal large B-cell lymphomas and 41% (20/49) of classic HL cases, but only 2.6% (4/152) of PTCL tumor cells expressed PD-L2, while all ENKTL tissues lacked PD-L2 expression (Panjwani et al., 2018).