POU1F1 and neoplasm: Finally, a recent study, clustering pituitary tumors by RNA-seq analysis in three groups coinciding with canonical lineage transcription factors [i.e., TBX19, NR5A1 (SF1) and POU1F1 (PIT1)], did not reveal a transcriptomic link with the (normal) stem cell population, but suggested that the “tumor progenitor cells” (TSC) derive from already (partially) committed cells expressing the respective transcription factor (99).