OP-7 - The clinical significance of lymphocyte activation gene 3 for ovarian clear cell carcinoma

Abstract

Ovarian clear cell carcinoma (OCCC) is resistant to platinum-based chemotherapy. The use of immune checkpoint inhibitors is expected to be a new strategy for its treatment. Lymphocyte activation gene 3 (LAG-3), an immune checkpoint, is a poor prognostic factor and a new therapeutic target for several malignancies. In this study, we demonstrated a correlation between LAG-3 expression and the clinicopathological features of OCCC. We evaluated LAG-3 expression in tumor-infiltrating lymphocytes (TILs) by immunohistochemistry using tissue microarrays containing surgically resected specimens from 171 patients with OCCC. The LAG-3-positive cases were 48 (28.1%). The expression of LAG-3 significantly increased in patients with advanced stages (P = 0.036) and recurrence (P = 0.012). Using the Kaplan−Meier method, LAG-3 expression was observed to be correlated with poorer overall survival (P = 0.020) and progression-free survival (P = 0.019) than no expression. Multivariate analysis regarded LAG-3 expression (HR = 1.86; 95% CI, 1.00−3.44, P = 0.049) and residual tumor (HR = 9.71; 95% CI, 5.13−18.52, P < 0.001) as independent prognostic factors. In this study, it is clear that LAG-3 expression in patients with OCCC is a useful biomarker for predicting prognosis and may be a new therapeutic target.