Ubiquitin-specific protease 10 (USP10), a novel deubiquitinating enzyme, is associated with androgen receptor transcriptional activity and pathological processes of tumor. However, information between USP10 and the adrenal gland is limited. In particular, the role of USP10 in adrenal tumors has not been elucidated yet. This study aims to investigate the expression of USP10 in the human normal adrenal gland and various adrenal tumors. Tissue samples were obtained from 30 adrenocortical adenomas, nine adrenocortical adenocarcinomas, and 20 pheochromocytomas following laparoscopic surgery. Twenty normal adrenal glands were obtained from kidney surgical resection conducted due to renal cell carcinomas. USP10 expression was investigated on protein levels using immunohistochemistry and on mRNA levels using bioinformatics analysis in the Gene Expression Omnibus (GEO) Datasets. In the 20 cases of normal adrenal glands analyzed, USP10 protein was constantly expressed in situ in the cortex of the adrenal glands, but in the medulla of the gland, only the sustentacular cells were detected positive. In adrenal tumors, detectable levels of USP10 protein were found in 100 % (30/30) adrenocortical adenomas, 88.89 % (8/9) adrenocortical carcinomas, and 10 % (2/20) pheochromocytomas. Bioinformatics analysis did not show a significant difference in USP10 messenger RNA (mRNA) expression between adrenal tumors and normal adrenal gland tissues. A positive USP10 immunoreaction can be useful in distinguishing adrenal cortical tumors from pheochromocytoma.
Keywords: Adrenal gland; Adrenocortical adenoma; Adrenocortical carcinoma; Pheochromocytoma; USP10.