Exploring the prognostic role of PD-L1 in pediatric adrenocortical tumors

Prognosis in advanced adrenocortical carcinomas (ACC) is poor and available biomarkers are not enough to predict poor prognosis. PD-1-PD-L1 (Programmed Death/Ligand) pathway is an immune check point used in prognosis determination and treatment target of many solid tumors. This study is designed to determine the expression of PD-L1 in childhood ACC to determine its effect on prognosis. The data of the patients with adrenocortical tumor (ACT) in our department, between 2000 and 2020 were evaluated retrospectively. Clinical findings, pre/postoperative managements and survival outcomes of the patients were included. The pathology specimens were selected from the tissues obtained from the primary tumor, the metastases and the recurrent masses. Immunohistochemical evaluation of the PD-L1 and Wieneke scoring system were evaluated. 3% staining was considered significant for PD-L1 positivity. The median age of 24 patients diagnosed with ACT was 5.9 years, and the male/female ratio was 11/13. Thirteen patients had ACC and 11 patients had adrenocortical adenoma (ACA). Twelve patients had malignant tumor according to Wieneke scoring system. We detected PD-L1 positivity (5%) in the primary tumor and lung metastasis of a patient in the malignant category according to Wieneke scoring system. Primary tumor of a patient in the benign category (adrenocortical adenoma) and a patient in the malignant category had 3% positivity for PD-L1. Eight Patients in benign category and nine patients in malignant category had <3% positivity for PD-L1. In this study, no relationship was found between PD-L1 positivity and prognosis. On the other hand, PD-L1 positivity in the primary and metastatic tumor of a patient may be promising for possible treatment with immune check point blockage. Multicenter studies examining larger patient groups will be helpful to understand the importance of immune check points and to improve outcomes in childhood ACT.