Expression of Immune Response Markers in Arab Patients With Lung Cancer

• Published in: JCO global oncology Vol. 6; no. 6; pp. 1218 - 1224
• Main Authors: Jazieh, Abdul Rahman, Bounedjar, Adda, Bamefleh, Hanaa, Alfayea, Turki, Almaghraby, Hatim Q, Belarabi, Ayed, Ouahioune, Wahiba, Derbouz, Zoubir, Alkaiyat, Mohammad, Alkattan, Khaled, Damlaj, Moussab, Khalbuss, Walid E
• Format: Journal Article
• Language: English
• Published: United States American Society of Clinical Oncology 01.11.2020
• Subjects: Aged; Algeria; Arabs; Carcinoma, Non-Small-Cell Lung; Female; Humans; Immunity; Lung Neoplasms; Male; Saudi Arabia; Special; Saudi Arabia; Algeria
• DOI: 10.1200/GO.20.00107
• ISSN: 2687-8941

Programmed death-ligand 1 (PD-L1) is a marker for checkpoint inhibitor use in the management of solid tumors, especially in non-small-cell lung cancer (NSCLC). Our study was aimed at determining the patterns of PD-L1 expression and cluster of differentiation 8 (CD8) immunostains in patients with NSCLC in the Arab population. Archival tumor tissue from patients with a confirmed diagnosis of NSCLC were obtained and stained for PD-L1 with antibody 22C3, using immunohistochemistry staining and giving the tumor proportion score (TPS) as a percentage from 0%-100% of stained tumor cells. Tumors were categorized into negative expressers (TPS < 1%), low positive (TPS, 1%-49%), and high positive (TPS, 50%-100%). Correlation of expression with clinical and pathologic features, including CD8-positive (CD8+) lymphocyte density, was also analyzed. Two hundred patients with NSCLC were included in the study from 6 centers in Saudi Arabia and Algeria. Median age was 65 years (28-93 years), and the majority were men (75%) with stage 4 NSCLC (64%). The TPS was high in 37 patients (18%), low in 60 patients (30%), and negative in 103 patients (52%). In a univariate analysis, the following were significant predictors of any PD-L1 expression (> 1%): male sex, being Saudi national patients, high expression of CD8+, and presence of tumor-infiltrating lymphocytes. In the multivariate analysis, only high expression of CD8+ cells (≥ 2+) was significant, with an odds ratio of 4.4 (95% CI, 1.5 to 12.9; .003). PD-L1 expression in our population is similar to the published literature and correlated with the density of CD8+ cells. Validation of the predictive value of this marker in our population and identifying easier and reliable methods to test for it are warranted.