Characterization of IBC-1, a Novel Putative Breast Cancer Prognostic and Survival Factor

摘要

Using SAGE(Serial Analysis of Gene Expression) we identified a SAGE tag that was only present in invasive breast carcinomas and their lymph node metastases. The transcript corresponding to this SAGE tag, IBC-1 (Invasive Breast Cancer-1)/dermcidin (DCD) encodes a secreted protein normally expressed only in the pons of the brain and sweat glands. Array CGH, FISH, and immunohistochemical analyses determined that IBC-1/DCD is overexpressed in approximately 10% of invasive breast carcinomas, in some cases its overexpression is coupled with a focal copy number gain of its locus at 12q13.1, and its expression is associated with advanced clinical stage and poor prognosis. Expression of IBC-1/DCD in breast cancer cells promotes cell growth and survival, and reduces serum dependency. Putative high and low affinity receptors for IBC-1/DCD are present on the cell surface of breast carcinomas and neurons of the brain. Based on this data we hypothesize that IBC-1/DCD may play a role in tumorigenesis via enhancing cell growth and survival in a subset of breast carcinomas.