We thank J. Massague and S. Tavazoie for MCF7, MDA231-Par, its metastatic derivatives and CN34-LM1 cell line, A. Dent for c-JUN, R.A. Weinberg for SOX4 construct, S.J. Kang and F. Miller for RAW cells and mouse mammary tumour cell lines, W.-D. This evidence concerns the gene SOX4 and breast cancer.