SKAP1 (src kinase associated phosphoprotein 1) is a cytosolic adapter protein that primarily functions in T cell receptor (TCR) signaling and immune cell adhesion. In normal immune function, SKAP1 positively regulates TCR-mediated signaling by enhancing the MAP kinase pathway and promoting LFA-1 integrin clustering on T cell surfaces, facilitating optimal adhesion between T cells and antigen-presenting cells 1. However, emerging evidence reveals unexpected roles in cancer pathogenesis. SKAP1 expression is significantly elevated in multiple cancers including colorectal, gastric, and pancreatic neuroendocrine tumors, where high levels independently predict poor survival 234. In colorectal cancer, SKAP1 expressed by tumor cells—rather than immune cells—promotes growth through the NFATc1/CXCL8 axis, enhancing neutrophil extracellular trap formation that impairs antitumor immunity 2. In gastric cancer, SKAP1 activates JAK1/PI3K/AKT signaling to promote cell proliferation and invasion while predicting poor immunotherapy response 3. A competing endogenous RNA network regulates SKAP1 via miR-218-5p in colorectal cancer 5. Conversely, genetic studies indicate decreased SKAP1 expression in blood increases endometrial cancer risk, suggesting context-dependent effects on immune surveillance 6. SKAP1 additionally emerges as a plasma biomarker associated with Alzheimer's disease severity 7. These findings position SKAP1 as a multifunctional molecule with divergent roles in immune regulation and cancer biology.