VSTM2A (V-set and transmembrane domain containing 2A) is a multifunctional protein that plays distinct roles in adipogenesis, immune regulation, and cancer biology. In adipose tissue development, VSTM2A is expressed and secreted by committed preadipocytes, where it promotes adipogenic commitment by modulating BMP signaling and activating PPARγ2 1. VSTM2A-producing cells associate with vasculature and express common surface markers of adipocyte progenitors 1. In immune regulation, VSTM2A functions as an immunomodulatory protein that antagonizes the PD-L1/PD-1 interaction through direct binding via their IgV domains with high affinity (0.7-2.5 nM) 2. This interaction enhances T cell activation, increases IL-2 production, and promotes cytotoxic T cell anti-tumor responses through granzyme B and IFN-γ release 2. Clinically, VSTM2A serves as a highly specific biomarker for mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney, with 99.2% diagnostic efficacy 3. The protein is frequently silenced during colorectal carcinogenesis and correlates with immune infiltration 24. Additionally, VSTM2A has been identified as a potential biomarker in cerebrospinal fluid for Parkinson's disease 5.