SH2D3C (SH2 domain containing 3C) is an adaptor protein located on chromosome 9.11-q34.13 that contains both an SH2 domain and a Ras GEF-like domain, classifying it as a novel SH2-containing protein (NSP3) 1. The protein is involved in regulation of cell adhesion, migration, and tissue organization through its interactions with signaling proteins 1. SH2D3C localizes to the cytosol and membrane ruffles, where it binds to DPP3 (dipeptidyl peptidase 3) via its C-terminal Ras GEF-like domain 1. Functionally, SH2D3C participates in cellular stress responses and the JNK signaling cascade, with evidence suggesting involvement in the BCAR1/CAS-mediated JNK activation pathway. Clinically, SH2D3C has emerged as a significant biomarker across multiple disease contexts: it is overexpressed in Gram-positive bacterial sepsis in preterm infants 2, correlates with poor prognosis in acute myeloid leukemia 3, participates in myocardial ischemia-reperfusion injury responses 4, and serves as a potential diagnostic biomarker for Sjögren's syndrome based on alternative splicing patterns 5. Additionally, SH2D3C shows methylation changes associated with fetal development 6, and inclusion in prognostic models for head and neck squamous cell carcinoma 7.