CTTN is overexpressed in breast cancer and squamous cell carcinomas of the head and neck. Cortactin is localized in the cytoplasm and in areas of the cell-substratum contacts. This gene has two roles: (1) regulating the interactions between components of adherens-type junctions and (2) organizing the cytoskeleton and cell adhesion structures of epithelia and carcinoma cells. During apoptosis, cortactin is degraded in a caspase-dependent manner. The aberrant regulation of CTTN contributes to tumor cell invasion and metastasis. Three splice variants that encode different isoforms have been identified for CTTN.