TMPRSS4 (Transmembrane Protease, Serine 4): TMPRSS4 is a member of the transmembrane serine protease family, located on the cell surface and involved in activating proteins by cleaving peptide bonds. TMPRSS4 plays important roles in physiological and pathological processes, including cell migration, invasion, and the regulation of epithelial-mesenchymal transition (EMT), which is critical for development, wound healing, and cancer metastasis. Its overexpression has been linked to the progression of various cancers, making TMPRSS4 a potential biomarker for cancer diagnosis and prognosis.