The present invention relates to nucleotide sequences, including expressed sequence tags (ESTs), oligonucleotide probes, polypeptides, antagonists and agonists vectors and host cells expressing, and immunoadhesions and antibodies to PRO201, PRO308 or PRO309 polypeptides. The invention further relates to compositions and method for the diagnosis and treatment of neoplastic cell growth and proliferation in mammals, including humans. The invention is based in part on the identification of genes that are amplified in the genome of tumor cells. Such gene amplification is expected to be associated with the overexpression of the gene product and contribute to tumorigenesis. Accordingly, the proteins encoded by the amplified genes are believed to be useful targents for the diagnosis and/or treatment (including prevention) of certain tumors (e.g., cancer) and may act as predictors of the prognosis of tumor treatment.