Herrera-Martinez, YiraldineContreras Gonzalez, María JosePedraza-Arevalo, SergioGuerrero Martinez, Maria Del CarmenRodrigo Martinnez, AngelaGonzalez Menchen, AlbertoBlanco Molina, Maria AngelesGalvez-Moreno, Maria AngelesMoreno-Vega, Alberto LLuque, Raul MHerrera-Martinez, Aura D2023-05-032023-05-032021-12-23Herrera-Martínez Y, Contreras González MJ, Pedraza-Arévalo S, Guerrero Martínez MDC, Rodrigo Martínez Á, González Menchen A, et al. Calcitriol-Mediated Hypercalcemia, Somatostatin Receptors Expression and 25-Hydroxyvitamin D3-1α- Hydroxylase in GIST Tumors. Front Endocrinol (Lausanne). 2022 Jan 26;12:8123851664-2392http://hdl.handle.net/10668/20556Hypercalcemia is a common complication in cancer patients Mainly caused by Parathyroid hormone-related protein (PTHrP) secretion and metastasis. Calcitriol secretion is a rare source of hypercalcemia in solid tumors, especially in gastrointestinal stromal tumors (GIST). We present a case report of a female patient with a 23 cm gastric GIST that expressed somatostatin-receptors and presented with severe hypercalcemia due to calcitriol secretion. Calcium control was achieved with medical treatment before the use of targeted-directed therapies. Surgery was performed and allowed complete tumor resection. Two years later, patient remains free of disease. Molecular analysis revealed the mRNA expression of 25-hydroxyvitamin D3-1-hydroxylase (1αOHase) and vitamin-D receptors in the tumor cells, confirming the calcitriol-mediated mechanism. Furthermore, the expression of the endotoxin recognition factors CD14 and TLR4 suggests an inflammatory mediated mechanism. Finally, the expression of somatostatin-receptors, especially SST2 might have been related with clinical evolution and prognosis in this patient.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/GIST tumorCalcitriolCorticoidsHypercalcemiaSomatostatin receptorsCalcifediolCalcitriolFemaleGastrointestinal stromal tumorsHumansHypercalcemiaMixed function oxygenasesReceptors, somatostatinVitamin Dresearch article35154010open accessHipercalcemiaOxigenasas de función mixtaReceptores de somatostatinaTumores del estroma gastrointestinalVitamina D10.3389/fendo.2021.812385PMC8826724https://www.frontiersin.org/articles/10.3389/fendo.2021.812385/pdfhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC8826724/pdf