CCL4 and breast cancer: Finally, we used Ingenuity Pathway Analysis (IPA) to evaluate the pathway, disease and functional annotations for a 10 gene set comprised of PEAK1, PEAK1-associated/dependent genes from the mesenchymal tumor stroma (i.e., SNAI2, INHBA, CCL4 and GDF5) and markers identified in our CycIF screen to be enriched in HER2-positive breast cancer cells when exposed to PEAK1-expressing MSC (i.e., AKT1, H2AFX, MCL1, GRP78 and VIM) (Fig. 8r–s).