GPR137C is a G protein-coupled receptor localized to the lysosomal membrane that may regulate MTORC1 complex translocation to lysosomes [UniProt]. The protein appears to function as a positive regulator of TORC1 signaling, a pathway critical for cell growth and metabolism. Mechanistically, GPR137C transcription is regulated by G-quadruplex (G4) structures in its promoter that facilitate hypomethylation and gene activation 1. The protein's target genes are involved in cell growth, bone ossification, and cartilage development/differentiation, potentially operating through MAPK signaling pathways 2. Clinically, GPR137C has emerged as a novel biomarker with disease relevance across multiple cancer types. In prostate cancer, GPR137C promotes tumor microenvironment remodeling by enhancing immune cell infiltration, thereby driving cancer progression, and is proposed as both a prognostic biomarker and therapeutic target for GPCR-targeted drug development 1. In small cell lung cancer, GPR137C is identified as a differentially expressed gene with altered upstream miRNA regulation (GPR137C-hsa-miR-1-3p), suggesting it may play a key role in cancer prognosis 3. These findings indicate GPR137C represents a promising therapeutic nexus across malignancies, though further mechanistic validation is needed.