Contactin 1 (CNTN1) is a cell adhesion molecule that belongs to the immunoglobulin superfamily and is anchored on the cell surface via glycosylphosphatidylinositol (GPI). It plays a crucial role in the development and growth of the nervous system and has recently gained research attention due to its aberrant expression and function in various types of cancer. In cancer research, CNTN1 has been found to be dysregulated in many human cancers and is closely associated with cancer progression and metastasis. Abnormal expression of CNTN1 is correlated with the advancement of cancer and poor prognosis. It functions in various signaling pathways in cancer, such as the vascular endothelial growth factor C (VEGFC)-VEGF receptor 3 (VEGFR3)/fms-related tyrosine kinase 4 (Flt4) axis, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), Notch signaling pathway, and the epithelial-mesenchymal transition (EMT) process. The role of CNTN1 in cancer-stroma interactions is particularly significant, as it promotes these interactions to activate the complex network required for cancer progression and metastasis. In breast cancer, the expression of CNTN1 is associated with genes that function in cancer-stroma interactions and skeletal system development, suggesting its potential role in bone metastasis of breast cancer. Additionally, the role of CNTN1 in the nervous system is also under investigation. It is considered a specific antigen for chronic inflammatory demyelinating polyneuropathy and may play a role in the development and diseases of the nervous system.