In this review, we describe the role of genes located on chromosome 9p24 and their derived proteins in diverse subtypes of lymphomas, with a special focus on PDL1 and PDL2, which are becoming a central target of immunotherapy, not only in classical Hodgkin lymphoma but also in various types of solid cancers.
However, no study has examined the relationship or prognostic implication of PD-L1, PD-L2, PD-1, VEGF expression, and microvessel density (MVD) in classical Hodgkin lymphoma (cHL) patients.
Signaling between programmed cell death protein 1 (PD-1) and the PD-1 ligands (PD-L1, PD-L2) is essential for malignant Hodgkin Reed-Sternberg (HRS) cells to evade antitumor immunity in classical Hodgkin lymphoma (cHL).
The relationships between altered expression of β<sub>2</sub>-microglobulin (β<sub>2</sub>M), MHC class I, and MHC class II by HRS cells, PD-L1/PD-L2 amplification, and clinical outcome in cHL are poorly defined.