Fig. 1

Immune checkpoint expression in thyroid cancer (TC) cells and human TC tissue samples. a. Mean Fluorescence Intensity for PD-1, PD-L1 and PD-L2 measured by flow cytometric analysis on H-6040 normal thyroid epithelial cells, PTC-derived cell lines (BcPAP and TPC-1), and ATC-derived cell lines (8505c, CAL62, SW1736, FRO, BHT101, HTH7, OCUT1). Data are presented as mean ± SD. * P < 0.05 compared to the H-6040 cells. b. Immunohistochemical staining of representative PTC samples with anti-PD-1 or anti-PD-L1 antibodies (20x and 40x). In the upper panels, PD-1 immunoreactivity in both thyroid epithelial cells and in infiltrating lymphocytes can be detected. Lower panels show PD-L1 immunoreactivity in a representative PTC sample