FOLR3 (folate receptor gamma) mediates cellular delivery of folate and reduced folic acid derivatives, with a secreted isoform that lacks folate-binding capacity 1. The protein functions as both a membrane-bound receptor and a secreted factor with distinct pathophysiological roles. Cellularly, FOLR3 enhances folic acid uptake and promotes cell growth in a folate-dependent manner 1. The secreted form of FOLR3 amplifies transforming growth factor-β (TGFβ) signaling in hepatic stellate cells through interaction with the serine protease HTRA1, driving extracellular matrix production and fibrosis progression in metabolic dysfunction-associated steatohepatitis (MASH) 2. FOLR3 expression correlates positively with fibrosis stage and is selectively elevated in MASH but absent in related metabolic disorders 2. Clinically, FOLR3 dysregulation associates with multiple diseases. Expression is downregulated in chr11 obstructive pulmonary disease monocyte/macrophages 3 and enriched in moderate-to-severe pediatric acute respiratory distress syndrome 4. FOLR3 is highly expressed in ovarian carcinoma compared to breast carcinoma and mesothelioma, supporting its utility as a therapeutic target 5. Blood FOLR3 hypomethylation specifically associates with lung squamous carcinoma diagnosis 6. Vitamin D supplementation upregulates FOLR3 expression, potentially improving COVID-19 outcomes through immunomodulation 7.