Kalman, Kovacs

Pituitary tumor transforming gene (PTTG) was initially found to be overexpressed in GH4 rat pituitary adenomas (PA). PTTG overexpression has been correlated with patient survival, tumor grade, and/or invasiveness in several tumors including those of thyroid, breast, lung, and colon. Studies of PTTG as a prognostic indicator in PAs are limited and show conflicting results. We investigated PTTG immunostaining in 79 PAs of different subtypes (growth hormone (GH), 12; prolactin (PRL), 6, adrenocorticotropic hormone (ACTH), 11, gonadotroph, 21; null cell, 29) in relation to clinico‐pathological variables including patient age and sex, as well as tumor size, and invasiveness. The streptavidin‐biotin‐peroxidase method was used, with a monoclonal PTTG antibody (Abcam, Cambridge, UK). PTTG expression was found to be cytoplasmic in all PAs, with highest levels being present in GH adenomas and lowest in the PRL ones. No correlation was found with patient age, sex, tumor size or invasiveness. Thus, it appears that PTTG cannot serve as a prognostic marker in patients with PAs. PTTG has been implicated in several tumorigenic processes including angiogenesis, DNA damage repair and invasiveness. PTTG overexpression in PA warrants further research into its role in PA initiation and progression.