GRN and cancer: Progranulin, also known as proepithelin, PCDGF (PC-derived growth factor), granulin-epithelin precursor or acrogranin, is an evolutionary-conserved, secreted glycoprotein containing 7 and a half granulin (GRN) repeats which plays an important role as a bona fide growth factor in cell proliferation, angiogenesis, wound healing and transformation in several cancer systems [5–7].