In contrast, the factors whose expression was dependent upon PEAK1 in MSCs (i.e., CCL4, INHBA and GDF5) displayed significantly higher transcript levels in breast cancer stroma across both studies, with INHBA/activin-A showing the greatest average fold-change increase in malignant over normal breast stroma (Fig. 7c, right three graphs). This evidence concerns the gene GDF5 and breast carcinoma.