SRCIN1 (SRC kinase signaling inhibitor 1) encodes the p140Cap adaptor protein that functions as a scaffold molecule regulating multiple cellular processes through SRC kinase signaling modulation 1. The protein acts as a tumor suppressor in several cancer types, with high expression correlating with better patient outcomes in breast cancer and neuroblastoma 2. In breast cancer, SRCIN1 hypermethylation occurs in 61.8% of cases and correlates with unfavorable 5-year survival, while knockdown decreases cancer cell viability through downregulation of ESR1, BCL2, and cyclin proteins 3. However, SRCIN1 demonstrates context-dependent roles, as overexpression promotes colorectal cancer growth and metastasis through Wnt/β-catenin pathway activation 4. The protein regulates epithelial-mesenchymal transition (EMT), with overexpression inhibiting EMT in osteosarcoma by promoting E-cadherin and suppressing N-cadherin, Vimentin, and Snail expression 5. SRCIN1 is targeted by multiple regulatory mechanisms, including miR-657 in non-small cell lung cancer, where its downregulation promotes tumor growth and EMT via Slug pathway activation 6. The protein also participates in pre-metastatic niche formation, where exosomal miRNA targeting of SRCIN1 activates SRC signaling in peritoneal macrophages, creating immunosuppressive environments that facilitate metastasis 7.