Clinical presentation and recurrence of pituitary neuroendocrine tumors: results from a single referral center in Colombia.

INTRODUCTION: Pituitary neuroendocrine tumors (PitNETs) represent 15-18.2% of all intracranial tumors. Their clinical presentation can range from chronic headache, visual defects, hypopituitarism to hormone excess syndromes. PitNETS are commonly classified as functioning neuroendocrine tumors (F-PitNETs) and non-functioning neuroendocrine tumors (NF-PitNETs). At the moment, new classification has emerged based on cell lineages. Almost 50% of all patients with PitNETs require surgical intervention, and about 25% of these have residual and persistent disease that may require additional management. SUBJECTS AND METHODS: A retrospective cohort of medical records of patients with PitNETs, aiming to describe the incidence of recurrence of patients who received surgical treatment over a 12 month follow up period at San Jose Hospital (SJH) in Bogotá, Colombia, over an observation period of 10 years. Furthermore, clinical presentation, biochemical characteristics and immunohistochemistry, postoperative complications are detailed. RESULTS: Eight hundred and eighty-seven patients with pituitary tumors were included in the cohort; 83% (737/887) had a diagnosis of PitNET. Of these, 18.9% (140) received surgical management. The majority 58% (98/140) had nonfunctional-PitNETs (NF-PitNETs), followed by growth-hormone-secreting pituitary adenoma (22.1%; 33/140), adrenocorticotropic- hormone-secreting pituitary adenoma (9.3%; 13/140), and prolactinomas (9.3%; 13/140). A recurrence was found in 45.71% (64/140), subclassified as biochemical in 15.71% (22/140), controlled with medications in 20% (28/140), and remission occurred in 18.57% (26/140). CONCLUSION: Clinical presentation and incidence of recurrence in patients with PitNETs in a referral center in Colombia are similar to other surgical cohorts with low cure rates and high recurrence.

Connexin Expression in Pituitary Adenomas and the Effects of Overexpression of Connexin 43 in Pituitary Tumor Cell Lines.

Gap junction intercellular communication (GJIC) is considered a key mechanism in the regulation of tissue homeostasis. GJIC structures are organized in two transmembrane channels, with each channel formed by connexins (Cxs). GJIC and Cxs expression alterations are related to the process of tumorigenesis in different cell types. Pituitary neuroendocrine tumors (PitNETs) represent 15-20% of intracranial neoplasms, and usually display benign behavior. Nevertheless, some may have aggressive behavior, invading adjacent tissues, and featuring a high proliferation rate. We aimed to assess the expression and relevance of GJIC and Cxs proteins in PitNETs. We evaluated the mRNA expression levels of Cx26, 32, and 43, and the protein expression of Cx43 in a series of PitNETs. In addition, we overexpressed Cx43 in pituitary tumor cell lines. At the mRNA level, we observed variable expression of all the connexins in the tumor samples. Cx43 protein expression was absent in most of the pituitary tumor samples that were studied. Moreover, in vitro studies revealed that the overexpression of Cx43 decreases cell growth and induces apoptosis in pituitary tumor cell lines. Our results indicate that the downregulation of Cx43 protein might be involved in the tumorigenesis of most pituitary adenomas and have a potential therapeutic value for pituitary tumor therapy.