Transcriptome and methylome analysis reveal three cellular origins of pituitary tumors

The pituitary tumors (PA) arise in adenohypophyseal cells and are the second most common tumor in central nervous system. Reflective of their monoclonal cell of origin these tumors could be classified according to the hormone that they produce. The mutational and copy number variation burden in these tumors are scarce, indicating other molecular events are involved in pituitary tumorigenesis. Here we show throughout transcriptome and methylome analysis that there are three readily distinctive molecular signatures. The first group is comprised by the gonadotropes, null cell and silent corticotroph PA, the second group comprised by ACTH PA and the group cluster together the TSH-, PRL- and GH- PA. These groups showed CACNA2D4, EPHA4 and SLIT1 gene up-regulation, respectively. Pathway enrichment analysis support the previous observations. The calcium signaling pathway is characteristic for gonadotropes null cell and silent corticotroph, the Renin-Angiotensin system for the ACTH PA and the Fatty acid metabolisms for the TSH-, PRL-, GH- cluster. The analysis of scRNA-seq from non-tumoral pituitary tissue revealed that these three groups originate since the pituitary development/embryogenesis. The immune cell infiltration landscape revealed that PA could be potentially infiltrated by NK and mast cells. Taken together these results correlate with the expression of the NR5A1, TBX19 and POU1F1 transcription factors, which drive pituitary embryogenesis and theoretically tumorigenesis and potentially indicates three divergent cell precursors cells. We used microarrays to detail the molecular alteration in PA compared to non-tumoral gland. CNFPA, ACTH-, GH-, PRL-, and TSH- adenomas were compared against non-tumoral pituitary gland.