Programmed Death-Ligand 1 Expression in Papillary Thyroid Cancer and Its Correlation with Clinicopathologic Factors and Recurrence.
Programmed death-ligand 1 (PD-L1) expression has been reported in several malignancies, but the expression of PD-L1 in papillary thyroid cancer (PTC) has been characterized rarely. The aim of this study was to assess the significance of PD-L1 expression and its associations with clinicopathologic factors and disease outcome in PTC.



Immunohistochemistry staining was conducted retrospectively to evaluate the expression of PD-L1 in a total of 260 PTC tumors and corresponding non-tumor tissues. The correlations between PD-L1 expressions with clinicopathologic features and recurrence-free survival (RFS) were analyzed.



PD-L1 expression was positive in 52.3% (136/260) of PTC tumor tissues, which was significantly higher than in corresponding non-tumor thyroid tissues. In clinicopathologic analyses, this positive staining of PD-L1 was positively linked to multifocality (p = 0.001) and extrathyroidal extension (p = 0.001). In multivariate Cox regression analysis, positive PD-L1 expression in tumor tissue was significantly associated with worse RFS (hazard ratio 2.825 [confidence interval 1.149-6.943], p = 0.024). In subgroup analyses based on clinicopathologic factors, positive PD-L1 staining of tumor tissue was associated with worse RFS in males (p = 0.001), older patients (≥45 years; p = 0.001), and patients with a primary tumor size >4 cm (p = 0.002), multifocal tumors (p = 0.031), extrathyroidal extension (p = 0.012), and lymph node metastasis (p = 0.004). In contrast, positive PD-L1 staining predicted worse RFS in the subgroup of patients without Hashimoto's thyroiditis (p = 0.001) and treated with total thyroidectomy (p = 0.019).



PD-L1 is important in determining aggressiveness of PTC and could predict the prognosis of patients. Therefore, inhibition of PD-L1 is suggested as a potential strategy for the treatment of advanced PTC with high expression of PD-L1.
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .|2 Department of General Surgery, Minhang Hospital, Fudan University , Shanghai, China .
Rong-Liang
RL
Shi
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Ning
N
Qu
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Ting-Xian
TX
Luo
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Jun
J
Xiang
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Tian
T
Liao
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Guo-Hua
GH
Sun
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Yu
Y
Wang
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Yu-Long
YL
Wang
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Cai-Ping
CP
Huang
1 Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University , Shanghai, China .
Qing-Hai
QH
Ji
D000328:Adult; D060890:B7-H1 Antigen / Q000378:metabolism*; D002291:Carcinoma, Papillary / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D050031:Hashimoto Disease / Q000150:complications; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy; D047368:Tumor Burden
D060890:B7-H1 Antigen; C423236:CD274 protein, human
biological marker; papillary thyroid cancer; programmed death-ligand 1; survival analysis