Archive | 2021
Expression of Programmed Death Ligand 2 in Patients with Thymoma and Thymomatous Myasthenia Gravis
Abstract
\n Purpose: The purpose of this study was to examine the expression of PD-L2 in thymoma and thymomatous myasthenia gravis (MG). Methods: The records of 70 patients with thymoma who underwent surgical resection between January 2017 and December 2018 were retrospectively reviewed. Thymoma PD-L2 expression was evaluated by immunohistochemistry (IHC) staining. Associations between PD-L2 expression and clinicopathological features were examined. Results: PD-L2 expression was positive in 41 patients (58.6%) and negative in 29 patients (41.4%). Of the patients, 33 had thymomatous MG. Patients with MG were more likely to be ≤ 50 years of age (69.70% vs. 35.14%), have higher WHO type (84.85% vs. 64.86%), smaller tumor size (4.09 ± 2.33 vs. 6.47 ± 2.42 cm), have positive PD-L2 expression (78.79% vs. 40.54%), and have higher PD-L2 expression intensity, ratio, and score (all, P < 0.05). Positive PD-L2 expression was associated with higher WHO type, higher Masaoka-Koga stage, smaller tumor size, ectopic thymus, and MG (all, P < 0.05). Factors significantly associated with MG were age > 50 years (OR = 0.09, 95% CI: 0.02 to 0.39), tumor size > 5 cm (OR = 0.22, 95% CI: 0.06 to 0.82), and positive PD-L2 expression (OR = 9.25, 95% CI: 1.93 to 44.30) (all, P < 0.05; Table 3).Conclusion: Thymoma PD-L2 expression is significantly associated with thymomatous MG and WHO histological type B2 and B3.