The primary aim of this study was to analyze samples from different adrenal diseases, adrenocortical carcinoma, adrenocortical adenoma, and pheochromocytoma, and compare them with normal adrenal tissue to determine whether the expression levels of the mitochondrial open reading frame of the 12S rRNA type-c (MOTS-c) gene and protein vary between different types of adrenal tumors compared to healthy controls using qPCR, ELISA, and IHC methods. This evidence concerns the gene MT-RNR1 and pheochromocytoma.