An important caveat to keep in mind as well is that the administration of HSP27 may pose risks in the case of cancer, since extracellular HSP27 has been shown to promote (i) the transendothelial migration of primary tumor cells (49) and (ii) the differentiation of macrophages to phenotypes that tolerate human breast cancer cell progression (48). This evidence concerns the gene HSPB1 and breast carcinoma.