Since EGFL7 is a plasma membrane-associated sialidase (lysosomal sialidase) that could accumulate at distant sites from the producing cells [15], it is impossible to answer if the elevated expression of EGFL7 transcripts observed in several human cancer tumors come from activated cancer epithelium or up-regulated endothelial cells of the surrounding stroma. The gene discussed is EGFL7; the disease is cancer.