Conclusion
We identified increased staining of PD-L1 in cHL and that of PD-L2 in PMBL. GZL had a pattern similar to that of cHL.
Methods
We explored the expression levels of PDLs and chromosomal anomalies in 67 cases: 34 cases with cHL, 20 with PMBL, and 13 with GZL, using immunohistochemical analyses and Fluorescence In Situ Hybridization (FISH).
Results
Twenty-one cHL (62%), 3 PMBL (15%), and 6 GZL (46%) cases showed staining to PD-L1 antibodies in more than 70% of tumor cells. Two cHL (6%), 10 PMBL (50%), and 3 GZL (23%) cases were not stained by PD-L1 antibodies. Patients over 40 years old manifest more frequent expression of PD-L1 in cHL. Proportion of tumors stained by PD-L2 antibody was increased in PMBL. FISH analyses with a PD-L1/PD-L2 probe detected 5 amplification, 1 gain, and 7 polysomy cases in cHL, 1 amplification and 1 polysomy case in GZL, and amplification in 1 PMBL case.