Although Mbd2 is generally believed to be a suppressor of gene activity through recruitment of the nucleosome remodeling and deacetylase (NuRD) complex and histone deacetylases to methylated promoters69 and a previous study in an isogenic model of breast cancer transformation showed that the majority of genes with differential expression following Mbd2 knockdown were upregulated70, we showed here that the majority of genes affected by Mbd2 deletion were silenced rather than activated. This evidence concerns the gene MBD2 and breast carcinoma.