Next to the possible paracrine, and EMT-affecting, signaling from cells within or around the bone metastatic niche to PC cells, compressed PC cells themselves also show altered gene expression of TGF-β1, PTHrP, IL6 and GDF15 as well as altered IL6 protein secretion in this study, which have the potential to affect their EMT-phenotype in an autocrine fashion, as well as altering the behavior of cells in the metastatic niche such as osteocytes and marrow stromal cells via paracrine signaling. Here, GDF15 is linked to pachyonychia congenita.