Background：

The coiled-coil domain is a structural motif found in proteins that are involved in a diverse array of biological functions such as the regulation of gene expression， cell division， membrane fusion and drug extrusion and delivery. CCDC45 (coiled-coil domain containing 45) is a 821 amino acid protein encoded by a gene that maps to human chromosome 17q23.3. Chromosome 17 comprises over 2.5% of the human genome and encodes over 1，200 genes. Two key tumor suppressor genes are associated with chromosome 17， namely， p53 and BRCA1. Tumor suppressor p53 is necessary for maintenance of cellular genetic integrity by moderating cell fate through DNA repair versus cell death. Malfunction or loss of p53 expression is associated with malignant cell growth and Li-Fraumeni syndrome. Like p53， BRCA1 is directly involved in DNA repair， though specifically it is recognized as a genetic determinant of early onset breast cancer and predisposition to cancers of the ovary， colon， prostate gland and fallopian tubes