FGFR2 and pituitary tumor: FGF2 is involved in stem cell maintenance and neurogenesis during embryonic development and during periods of stress or injury in the adult brain and is crucial for normal pituitary development.14,17 Downregulation of the FGF2 receptor (FGFR2) gene via promoter methylation leads to reduced growth factor receptor expression, allowing tumor cells to progress through the cell cycle.7,14 Pituitary tumor tissue contains downregulated FGFR2 in 52% of PitNETs, with methylation found in 45%.14