Fig. 1

Immunohistochemical staining against PD-1, PD-L1 and PD-L2. Representative images of FFPE samples immunostained with PD-1 (a-d), PD-L1 (e-h) and (i-l), original magnification: 200×. A, E and I represented negative expression of PD-1, PD-L1 and PD-L2, respectively. B-D, F-H and J-L represented different positive intensities (1+, 2+ and 3+) of PD-1, PD-L1 and PD-L2, respectively