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). The gene discussed is POU1F1; the disease is pituitary tumor.