PD-L1, PDK-1 and p-Akt are correlated in patients with papillary thyroid carcinoma

Abstract

Background. Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma. Objectives. To investigate the clinical significance of programmed death ligand 1 (PD-L1) and phosphoinositide-dependent protein kinase 1 (PDK1) in PTC. Material and methods. A total of 194 PTC patients were recruited. Contralateral normal thyroid tissues were obtained and used as controls (n = 80). The expression levels of PD-L1, PDK1 and p-Akt were determined using immunohistochemistry. Results. The PD-L1, PDK1 and p-Akt were upregulated in cancer tissues compared to the normal tissues. The mean optical density (MOD) values of PD-L1, PDK1 and p-Akt were significantly higher in the PTC tissues. The expression of PD-L1 positively correlated with the levels of PDK1 and p-Akt. In addition, the expression of PD-L1, PDK1 and p-Akt in PTC patients without chronic lymphocytic thyroiditis (CLT) was significantly higher than the expression of those proteins in the CLT patients. The patients with higher expression levels of PD-L1, PDK1 or p-Akt had remarkably larger tumors and higher rates of TNM III-IV, capsular infiltration, lymph node metastasis, and of recurrence. The Kaplan-Meier curve showed that patients with lower expression of PD-L1, PDK1 or p-Akt had significantly longer recurrence-free time. The logistic regression analysis revealed that only CLT, PD-L and capsular infiltration were risk factors for patients' five-year recurrence. Conclusions. The PD-L1, PDK1 and p-Akt were found to be positively correlated with a poor prognosis in PTC.