A gene that is a positive mediator of tumor growth and metastasis in certain cancer types is provided. This gene and corresponding polypeptide have diagnostic and therapeutic application for detecting and treating cancers that involve expression of SCC-S2 such as renal, ovarian, head and neck, breast, prostate, brain, chronic myelogenous leukemia, lung, lymphoblastic leukemia, and colorectal adenocarcinoma cells.