Proteomic profiling of mammary carcinomas identifies C7orf24, a gamma-glutamyl cyclotransferase, as a potential cancer biomarker.

Breast cancer is the leading cause of cancer deaths in women today and is the most common cancer (excluding skin cancers) among women in the Western world. Although cancers detected by screening mammography are significantly smaller than nonscreening ones, noninvasive biomarkers for detection of breast cancer as early as possible are an urgent need as the risk of recurrence and subsequent death is closely related to the stage of the disease at the time of primary surgery. A set of 123 primary breast tumors and matched normal tissue was analyzed by two-dimensional (2D) gel electrophoresis, and a novel protein, C7orf24, was identified as being upregulated in cancer cells. Protein expression levels of C7orf24 were evaluated by immunohistochemical assays to qualify deregulation of this protein. Analysis of C7orf24 expression showed up-regulation in 36.4 and 23.4% of cases present in the discovery sample set (123 samples) and in an independent large TMA validation data set (2197 samples) of clinically annotate...