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Background: Since most pituitary adenomas are benign, there is no model of pituitary adenomas that can be continuously cultured without genetic manipulation. In this study, we analyzed the genetic characteristics of the established cell lines by continuous culture of benign pituitary adenomas without genetic manipulation. Method: The pituitary adenoma was continuously cultured by modifying the conditional reprogramming (CR) method, and the morphology was observed and fluorescent immunostaining (IF) was performed. In addition, genetic characteristics were comprehensively analyzed, differences from the surgical samples were analyzed by enrichment analysis using GSEA, and network analysis was performed using cytoscape based on the protein-protein interaction database. (Results) 1) Of the 14 cases of pituitary adenoma that had undergone primary culture (median MIB-1 labeling index 1.5%), 12 cases were capable of continuous culture for more than 2 months. (6 months or more: 5 cases) 2) After 2 weeks of culturing, the cell morphology changed dramatically. These cultured cells were positive for follicular cell marker s100, ectodermal nervous system markers Nestin, Notch1, and mesodermal marker Vimentin. In these cells, synaptophysin, which was strongly positive in the surgical specimen collected at the same time as the culture, disappeared. 3) Enrichment analysis revealed that gene expression such as epithelial mesenchymal transition(EMT), angiogenesis, IL6 signaling via NFkB, extracellular degradation, integrin cell surface interaction increased in cultured cells, and gene expression such as neurotransmitter including synaptophysin decreased significantly.(Conclusion) 1) The modified CR method allowed continuous culture of pituitary adenoma cells. 2) The cultured cells showed characteristic change of EMT, which was seen in invasive pituitary adenoma.