Expression and Prognostic Significance of PD-L1 and NY-ESO1 in Gallbladder Carcinoma

Gallbladder cancer is a rare malignancy with a very high mortality, usually due to diagnosis in an advanced stage of the disease. Therefore, the aim of this study was to evaluate the clinical significance of cancer/testis antigen 1A (CTAG1A, NY-ESO1) and CD274 molecule (PD-L1, the ligand for programmed cell death protein 1) and their impact on the overall survival of patients with gallbladder cancer.

Using immunohistochemical staining, we determined the expression of NY-ESO1 in tumor cells (positivity: cytoplasmic/nuclear staining of any intensity in ≥50%) and PD-L1 in tumor cells and intratumoral immune cells (positivity: cytoplasmic/membranous staining of any intensity in ≥1%).

The median overall survival (OS) of 58 patients with gallbladder cancer in our cohort was 7 months, and depended on the clinical stage of the disease; the 5-year OS rate was 10%. NY-ESO1 was expressed in 69.1% of cases. Immune cells were PD-L1-positive in 36.4% of cases, while tumor cells expressed PD-L1 in only 10.9% of cases. In six cases (10.9%), neither of the studied proteins were expressed. NY-ESO1 expression was negatively correlated with PD-L1 expression in immune cells (p=0.021). NY-ESO1 showed no correlation with any clinicopathological parameters or OS. PD-L1 expression in immune cells was significantly higher in tumors with perineural invasion (r_s=0.318; p=0.018) and higher clinical disease stage (r_s=0.339; p=0.013) but showed no correlation with OS.

Patients whose gallbladder cancer expresses NY-ESO1 or PD-L1 might be candidates for immunotherapy.