Identification of the CAB2/hCOS16 Gene Required for the Repair of DNA Double‐strand Breaks on a Core Amplified Region of the 17ql2 Locus in Breast and Gastric Cancers

We previously reported that CAB1 and c‐ERBB‐2 genes were found to be located in a core amplified region of the 17q12 locus, which is frequently amplified in various cancers. During identification of this core region, CAB2, a human homologue of the yeast COS16 required for the repair of DNA double‐strand breaks was cloned. Autofluorescence analysis of cells transfected with its GFP fusion protein demonstrated that CAB2 translocates into vesicles, suggesting that overexpression of CAB2 may decrease intercellular Mn(2+) by accumulating it in the vesicles, in the same way as yeast COS16. This is the first report identifying all of the genes on the core amplified region of the 17q12 locus in breast and gastric cancers.