While due to lack of normal tissue from the adrenal medulla, the gene expression level of the PCCs was compared to the expression level of adenoma in the context of Conn's Syndrome as reference and thus to a different tissue, the degree of the overexpression was probably not overestimated as the expression of IGF2 in adults is restricted to the adrenal capsule and the periphery of the cortex (Baquedano et al. 2005), and the expression of IGF2 in normal adrenal medullary cells is below the expression level in benign tumors (Meyer-Rochow et al. 2010). This evidence concerns the gene IGF2 and adenoma.