The detection of PD-L1 expression in thyroid papillary carcinoma

Abstract

Background: Based on the confirmed diagnosis, surgery, adjuvant or neoadjuvant, targeted, and immune therapies are used depending on their tumor stage. PD-L1 is expressed on the surface of various cells. In cancer, PD-L1 is expressed on tumor cells, which interacts with PD-1 on T-cells and reduces its function to prevent the immune system from cancer. Immunotherapy with this immune inhibiting action is used in cancer therapy alongside chemotherapy and others. Detection of PD-L1 expression in thyroid cancer cases is significant for appropriate therapy selection. Therefore we considered that the detection of PD-L1 expression in thyroid cancer in our country. Aim: To detect PD-L1 expression in papillary thyroid carcinoma Materials and Methods: We collected 22 surgically removed formalin-fixed parafÏn embedded block tissue who underwent papillary thyroid carcinoma from 2018 to 2019 in the National Cancer center. In addition, PD-L1 expression was evaluated by immunohistochemistry. Results: In our study, patients aged from 19 to 71 with a mean age of 46.55±15. By gender, there were 86.04% female and 13.6% male. Among all collected cases, 7 were located in the left lobe, 6 were in the right lobe and 5 were bilaterally located. The diameters of the cases ranged from 0.5 cm to 10 cm, with a mean diameter of 1.6±0.5 cm. Among a total of 11 ≤1cm sized cases, 7 (63.6%) were stained PD-L1 positive, 4 (36.4%) were stained negatively and all of 7 ≥1 cm sized cases were stained positive. As of subtype arrangement, 12 (54.5%) of them were conventional variants and 10 (45.5%) of them were follicular variants. In correlated analysis between PD-L1 expression and pathological feature, 9 (40.9%) cases were stained positive, and 3 (13.6%) cases were stained negative from 12 conventional variants of papillary carcinoma samples and 8 (80%) cases were stained positive, 2 (20%) were stained negatively from total 10 follicular variants of papillary carcinoma cases. Conclusion: The expression of PD-L1 was detected in 77.3%(n=17) of papillary thyroid carcinoma by immunohistochemistry. There was no significant correlation between PD-L1 expression and pathological features of papillary thyroid carcinoma.