[Problem to be Solved] An object of the present invention is to provide novel means for the treatment and diagnosis of cancer. [Solution] The present inventors have obtained a monoclonal antibody against TMPRSS11E and found that this antibody binds to a native form of TMPRSS11E, and TMPRSS11E is highly expressed on the cell membranes of cancer cell lines in flow cytometry. This antibody exhibits antibody-dependent cell-mediated cytotoxicity activity (ADCC activity) and antitumor effect based on internalization activity and is promising as a therapeutic target. Moreover, this antibody has neutralization activity against protease activity and is also expected to have effect brought about by the inhibition of TMPRSS11E functions.
