This invention relates to the polynucleotides and the encoded polypeptides, including novel sequences, of human or non-human primate genes that are amplified in breast and/or other tumor tissues melanoma, as compared to the corresponding normal tissue. The invention also relates to modulators of such polynucleotides and polypeptides, for example, antibodies, that specifically bind to and/or interfere with the activity of this polypeptide, polynucleotide, its fragments, variants, and antagonists. The invention further relates to compositions containing such a polypeptide, polynucleotide, or modulators thereof and uses of such compositions in methods of treating or preventing cancer, by detecting this polynucleotide, polypeptide, or antibodies thereto in patient samples. The invention also provides diagnostic tests for breast cancer and melanoma, by identifying polypeptides and polynucleotides encoded by the cDNA sequence of the invention that correlate with those disorders.