Transcriptomic Profiles of Normal Pituitary Cells and Pituitary Neuroendocrine Tumor Cells

Simple Summary The molecular pathogenesis of pituitary neuroendocrine tumors (PitNETs) involves the interplay of many genes and transcription factors in the setting of a diverse altered tumor microenvironment. Recent advancements in molecular technologies, such as single-cell RNA sequencing, became essential in delineating specific cell types and identifying altered genes in both normal physiological states and diseases in the pituitary. This review discusses the recent progress made in characterizing the transcriptomic profiles of the normal pituitary gland and sporadic PitNETs and their significance. The pituitary gland is one of the most cellularly diverse regions of the brain. Recent advancements in transcriptomic biology, such as single-cell RNA sequencing, bring an unprecedented glimpse into the molecular composition of the pituitary, both in its normal physiological state and in disease. Deciphering the normal pituitary transcriptomic signatures provides a better insight into the ontological origin and development of five types of endocrine cells, a process involving complex cascades of transcription factors that are still being established. In parallel with these observations about normal pituitary development, recent transcriptomic findings on pituitary neuroendocrine tumors (PitNETs) demonstrate both preservations and changes in transcription factor expression patterns compared to those seen during gland development. Furthermore, recent studies also identify differentially expressed genes that drive various tumor behaviors, including hormone hypersecretion and tumor aggression. Understanding the comprehensive multiomic profiles of PitNETs is essential in developing molecular profile-based therapies for PitNETs not curable with current treatment modalities and could eventually help align PitNETs with the breakthroughs being made in applying precision medicine to other tumors.