title: Low expression of secreted frizzled-related protein 2 and nuclear accumulation of β-catenin in aggressive nonfunctioning pituitary adenoma.
abstract: The identification of a specific molecular marker for aggressiveness of nonfunctioning pituitary adenomas (NFPAs) is urgently required in order to guide the clinical diagnosis and treatment of NFPAs. In the present study, low expression of secreted frizzled-related protein 2 (sFRP2) in NFPAs was demonstrated by reverse transcription-quantitative polymerase chain reaction, western blot and immunohistochemical analyses. The results confirmed an abnormal accumulation of free β-catenin in the nuclei of NFPAs, which is the core step for the activation of the Wnt canonical signaling pathway. Furthermore, cyclin D1 and c-Myc, the downstream proteins of the Wnt canonical signaling pathway, were overexpressed in aggressive NFPAs. These findings demonstrated the activation of the Wnt canonical signaling pathway in aggressive NFPAs. In addition, sFRP2 expression was observed to be inversely correlated to the aggressiveness of NFPAs. Therefore, sFRP2 may act as a tumor suppressor through modulation of the cellular cytosolic pool of β-catenin in NFPAs. Furthermore, the expression of sFRP2 may serve as a biomarker for NFPAs aggressiveness and prognosis.
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Youtu
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Bai
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Linchuan
authors.initials: L
authors.lastname: Hong
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Shengyuan
authors.initials: S
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, P.R. China.
authors.forename: Yazhuo
authors.initials: Y
authors.lastname: Zhang
keywords: Wnt canonical signaling pathway; nonfunctioning pituitary adenoma; secreted frizzled-related protein 2; β-catenin