SLITRK4 (SLIT and NTRK like family member 4) is a membrane protein with dual functions in neural development and cancer progression. In the nervous system, SLITRK4 is involved in synaptogenesis and promotes synapse differentiation, while suppressing neurite outgrowth 1. CRISPR knockout screens have identified SLITRK4 as essential for neuronal differentiation, with mouse models showing marked neuroanatomical abnormalities including microcephaly 2. The protein is differentially expressed in various developmental contexts, appearing in decidua basalis tissue and being overexpressed in primary uterine leiomyosarcomas compared to metastases 34. In cancer, SLITRK4 functions as an oncogenic driver, particularly in liver metastasis. It is highly upregulated in colorectal cancer liver metastases and promotes tumorigenesis through PI3K/AKT/NFκB pathway activation 5. In gastric cancer, SLITRK4 interacts with CNPY3 to enhance TrkB receptor endocytosis and recycling, promoting liver metastasis 6. The protein is negatively regulated by miR-139-5p in hepatocellular carcinoma, where its overexpression increases cell invasion and proliferation 7. Recent studies have also identified SLITRK4 variants associated with age-related macular degeneration, suggesting broader roles in disease pathogenesis 8.