Perlecan is a major constituent of the glandular basement membrane (BM), the reactive stroma that surrounds the tumor in response to cancer-produced and growth factor-elicited signals, the vascular BM at sites of both intravasation and extravasation, and as a reticular network in the bone marrow metastatic niche [4, 9, 10]. Here, HSPG2 is linked to cancer.