SHC1 encodes a signaling adapter protein that plays critical roles in growth factor signaling, cellular stress responses, and aging processes. The gene produces multiple isoforms, with p46Shc and p52Shc functioning as initiators of the Ras signaling cascade by coupling activated receptor tyrosine kinases to downstream pathways through GRB2/SOS recruitment 1. The p66Shc isoform serves a distinct function in oxidative stress responses and longevity regulation, mediating endothelial dysfunction across various pathological conditions including hyperlipidemia, diabetes, and aging 2. SHC1 acts downstream of p53 during stress responses, promoting intracellular oxidant elevation and apoptosis 3. The protein demonstrates clinical significance as a biomarker, with upregulation observed across multiple cancer types and association with poor prognosis 4. In gastric cancer, SHC1 recruitment to HER2 activates MAPK and PI3K pathways, while its binding partner SHCBP1 regulates mitotic processes 1. Additionally, SHC1 serves as a therapeutic target, with microRNA 452 regulation maintaining cellular homeostasis during carcinogenesis 5. A longevity-associated polymorphism (Met410Val) has been identified, suggesting potential links between SHC1 variants and human lifespan 6.