Involvement of C12orf32 overexpression in breast carcinogenesis

Through genome-wide gene expression profile analysis of breast cancer, we identified a gene, chromosome 12 open reading frame 32 (C12orf32), to be involved in mammary carcinogenesis. Semiquantitative RT-PCR and Northern blot analysis confirmed C12orf32 overexpression in breast cancer cells and its almost undetectable level of expression in normal human tissues. Immunocytochemical staining analysis using breast cancer cell lines revealed a cell cycle-dependent subcellular localization of endogenous C12orf32 protein. Depletion of C12orf32 expression by small-hairpin RNA interference significantly suppressed the growth of breast cancer cell lines possibly due to the inhibition of G1/S transition and subsequent cell death. Western blot analysis indicated that a C12orf32 protein of 35 kDa predicted from the cDNA sequences was processed to a 16-kDa protein of (C12orf32-p16) which was accumulated in most of breast cancer cell lines examined. Our data suggest that C12orf32 is a promising molecular target for the development of novel anticancer drugs such as peptide vaccines and siRNA drugs.