PD-L1 Expression and Tumor-Infiltrating Lymphocytes in High-Risk and Metastatic Cutaneous Squamous Cell Carcinoma. (January 2019)

• Record Type: Journal Article
• Authors: Amoils, Misha; Kim, Jinah; Lee, Carolyn; Sunwoo, John B.; Colevas, A. Dimitrios; Aasi, Sumaira Z.; Hollmig, S. Tyler; Ma, Yifei; Divi, Vasu
• Is Part Of: Otolaryngology--head and neck surgery. Volume 160:Number 1(2019)
• Page Start: 93
• Page End: 99
• Publication Date: 2019-01
• Subjects: cutaneous HNSCC -- PD-L1 -- PD-1 -- cancer immunohistochemistry; Head -- Surgery -- Periodicals; Neck -- Surgery -- Periodicals; Otolaryngology -- Periodicals; 617.51
• DOI: 10.1177/0194599818788057
• Languages: English
• ISSNs: 0194-5998

Abstract

Objective: To characterize programmed death–ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) positivity for locally aggressive or regionally metastatic cutaneous head and neck squamous cell carcinoma (cHNSCC). Study Design: Retrospective chart review, followed by immunohistochemical staining of archived tumor specimens. Setting: Tertiary academic medical center. Subjects and Methods: After identification of 101 patients treated surgically for locally advanced or regionally metastatic cHNSCC, archived tissue was stained and graded for PD-L1 expression in addition to TIL presence. Cross-tabulation was performed to examine the association between either of these variables and clinicopathologic features and outcomes. Results: A total of 101 patients met inclusion criteria, but archived tissue was available only for 83 (31 primaries, 52 metastases). The majority of primary tumors demonstrated grade 1 PD-L1 staining, while grade 2 staining was more likely for metastases. Neither high- nor low-grade PD-L1 expression correlated with any clinicopathologic variable for primary tumors. However, for metastases, high-grade staining was significantly associated with regional recurrence (15 of 19, P = .02). TILs were present for 65% of primary tumors and 90% of regional metastases but did not correlate with any clinicopathologic variables. Conclusion: Diffuse expression of PD-L1 in this study highlights the possibility of using immunotherapy in the form of programmed death 1/PD-L1 blockade to improve treatment for this devastating disease. However, further studies are needed to clarify the significance of PD-L1 expression and TIL positivity for locally advanced or regionally metastatic cHNSCC.