The invention provides an antibody-drug conjugate comprising an anti-158P1D7 antibody or antigen binding fragment thereof conjugated to monomethyl auristatin E (MMAE), wherein the antibody or fragment thereof comprises a heavy chain variable region comprising an amino acid sequence at least 80% homologous to the heavy chain variable region amino acid sequence set forth in SEQ ID NO:7 and a light chain variable region comprising an amino acid sequence at least 80% homologous to the light chain variable region amino acid sequence set forth in SEQ ID NO:8.