Provides Antibodies which bind to the extracellular domain of the transmembrane receptor tyrosine protein kinase matriptasa. Also provided are Nucleic Acid molecules that encode Antibodies, Expression Vectors, host cells and Methods for expressing Antibodies.The Antibodies can be used for the treatment of cancer, including gastric cancer, colorectal cancer, prostate cancer, Breast Cancer, ovarian cancer, Lung Cancer, preferably SCLC, esophageal cancer, Head and Neck Cancer, pancreatic cancer, Lymphoma pref Erentemente non Hodgkin's lymphoma and Skin Cancer.Claim 1: isolated an Antibody or an Antigen binding portion thereof,Which: (a) binds to an epitope in the region of the stem of matriptasa which is recognized by an Antibody which comprises a variable region of heavy chain is the Amino Acid Sequence exposed in SEC ID no. 1 and a variable region of light chain that includes the sequence Amino Acids exposed in SEC ID no. 2Or (b) Competes for Binding to the region of the stem of matriptasa with an Antibody which comprises a variable region of heavy chain is the Amino Acid Sequence exposed in SEC ID no. 1, and a variable region of light chain is the Amino Acid Sequence exposed in SEC ID no. 2.Proporciona anticuerpos los cuales se unen al dominio extracelular del receptor transmembrana de tirosina - proteína quinasa Matriptasa. También se proveen moléculas de ácido nucleico que codifican los anticuerpos, vectores de expresión, células huéspedes y métodos para expresar los anticuerpos. Los anticuerpos pueden utilizarse para el tratamiento del cáncer, incluyendo cáncer gástrico, cáncer colorrectal, cáncer de próstata, cáncer mamario, cáncer de ovario, cáncer pulmonar, preferentemente SCLC, cáncer de esófago, cáncer de cabeza y cuello, cáncer pancreático, linfoma preferentemente linfoma no de Hodgkin y cáncer de piel. Reivindicación 1: Un anticuerpo aislado, o una porción de unión al antígeno del mismo, el cual: (a) se une a un epítopo en la región del tallo de Matriptasa
