To further investigate the function of DCD in breast cancer, here we describe the identification of a DCD splice variant (DCD-SV) and the consequences of downregulating DCD expression in the MDA-MB-361 human HER2+ breast cancer cell line and upregulating DCD in the MCF-7 human HER2- breast cancer cell line and in the SK-BR-3 human HER2+ amplified cell line. This evidence concerns the gene ERBB2 and breast carcinoma.