<p>Disclosed are: a monoclonal antibody which can specifically recognize the natural configuration of an extracellular domain of system ASC amino acid transporter 2 (ASCT2) and can bind to the extracellular domain, or an antibody fragment thereof; a hybridoma capable of producing the antibody; DNA encoding the antibody; a vector carrying the DNA, a transformant produced by introducing the vector; a method for producing an antibody or an antibody fragment thereof by using the hybridoma or the transformant; a therapeutic agent comprising the antibody or an antibody fragment thereof; and a diagnostic agent comprising the antibody or an antibody fragment thereof.</p>
