['Primary pigmented nodular adrenocortical disease (PPNAD) can occur as an isolated trait or part of Carney complex, a familial lentiginosis-multiple endocrine neoplasia syndrome frequently caused by mutations in PRKAR1A, which encodes the 1alpha regulatory subunit of protein kinase A (PKA). Because alterations in the insulin-like growth factor (IGF) axis, particularly IGF-II and IGF binding protein (IGFBP)-2 overexpression, have been implicated in sporadic adrenocortical tumors, we sought to examine the IGF axis in PPNAD.', 'RNA samples and paraffin-embedded sections were procured from adrenalectomy specimens of patients with PPNAD. Changes in expression of IGF axis components were evaluated by real-time quantitative RT-PCR and immunohistochemistry. NCI-H295R cells were used to study PKA and IGF axis signaling in adrenocortical cells in vitro.', 'IGFBP-2 mRNA level distinguished between the two genetic subtypes of this disease; increased IGFBP-2 expression in PRKAR1A mutation-positive PPNAD tissues was also confirmed by immunohistochemistry. Moreover, PKA inhibitors increased IGFBP-2 expression in NCI-H295R adrenocortical cells, and anti-IGFBP-2 antibody reduced their proliferation.'] Does primary pigmented nodular adrenocortical disease reveal insulin-like growth factor binding protein-2 regulation by protein kinase A?