Gad1, also known as glutamate decarboxylase 1, is an enzyme that catalyzes the production of γ -aminobutyric acid (GABA) from L -glutamic acid [5]. GABA is a prominent neurotransmitter, and thus Gad1 is crucial for neurotransmission. The gene is also associated with pathways like RAS/MAPK, Wnt/β -catenin, and GABAB receptor -mediated signaling, which are involved in various biological processes [1,2,3,6].

In glioma, overexpression of Gad1 inhibited cell proliferation, invasion, migration, promoted apoptosis, and enhanced sensitivity to cuproptosis by inhibiting the RAS/MAPK pathway [1]. In oral squamous cell carcinoma (OSCC), knockdown of Gad1 expression significantly inhibited cell proliferation, migration, and invasion by reducing GABA -mediated GABAB receptors [3]. In osteosarcoma, a Gad1 inhibitor suppressed tumor growth through the Wnt/β -catenin signaling pathway [6]. In castration -resistant prostate cancer, Gad1 promoted cancer progression and drug resistance [7]. In Gad1 knock -out rats, there were abundant spike -wave discharges in EEG, indicating a role of Gad1 -mediated GABA in suppressing epileptic brain activities [4].

In conclusion, Gad1 plays diverse roles in different biological processes and diseases. Through gene knockout models like in rats, it has been revealed that Gad1 is essential in maintaining normal neural functions, such as suppressing epileptic activities. In cancer, it can either act as a tumor suppressor as in glioma or promote tumor progression as seen in OSCC, osteosarcoma, and castration -resistant prostate cancer, highlighting its complex and context -dependent functions.