Afrogheh, Amir H.Wolkow, NatalieJakobiec, Frederick Albert2021-01-202021-01-202020Afrogheh, A. H. et al. (2020). PD-L1 and PD-L2 expression levels are low in primary and secondary adenoid cystic carcinomas of the orbit: Therapeutic implications. Ophthalmic Plastic and Reconstructive Surgery, 36(5), 444-4501537-267710.1097/IOP.0000000000001585http://hdl.handle.net/10566/5691To determine if there is a biologic rationale for using checkpoint inhibitor drugs targeting programmed cell death ligand 1 (PD-L1) and PD-L2 in the treatment of adenoid cystic carcinoma of the orbit. Methods: Twenty-three cases of adenoid cystic carcinoma involving the orbit (13 primary lacrimal gland, 5 secondarily extending into the orbit, and 5 unspecified) were examined histopathologically. Immunohistochemistry for PD-L1, PD-L2, and CD8 was performed. Charts were reviewed for clinical correlations. Results: Expression of PD-L1 and of PD-L2 was overall low in adenoid cystic carcinoma (mean expression 1.4 ± 0.9 of 5 for PD-L1, mean 0.83 ± 1.1 of 5 for PD-L2), and tumor-infiltrating CD8-positive T-lymphocytes were sparse (mean 1.1 ± 0.51 of 3). Only 13 of the 23 (57%) cases expressed PD-L1 as a combined positive score ≥1 of cells. No associations were found between expression levels of these markers and patient sex, tumor site of origin, Tumor, Node, Metastasis stage, or patient outcome.enPD-L1PD-L2Therapeutic implicationsAdenoid cysticDrugsArticle