To validate the results of the RNA-seq analysis and to extend the scope of the study beyond the 3 h time point in two cell lines, qRT-PCR was used to study the expression levels of 15 selected DEGs in MDA-MB-231 and T-47D cells as well as in five additional breast cancer cell lines (BT-474, HCC-1954, MCF-7, MDA-MB-361, and MDA-MB-436) and one normal breast epithelial cell line (MCF-10A) treated with BMP4 and vehicle for 3, 6 and 24 h. This evidence concerns the gene BMP4 and breast cancer.