The present invention provides fully human monoclonal antibodies that specifically bind to GPNMB, and uses thereof. Nucleotide sequences encoding, and amino acid sequences comprising, heavy and light chain immunoglobulin molecules, particularly sequences corresponding to contiguous heavy and light chain sequences spanning the framework regions and/or complementarity determining regions (CDRs) are provided. The present invention also provides immunoconjugates comprising anti-GPNMB antibodies and methods of using such immunoconjugates. The present invention further provides methods of treating breast cancer using antibodies that bind to GPNMB, immunoconjugates and other derivatives thereof.
