HDGF and cancer: As a mitogen, HDGF is highly expressed in the early developmental stage of several organs and decreases rapidly after birth [6–8], however, several findings recently suggested that HDGF is highly expressed in a variety of cancers [9, 10, 13, 14, 16, 18–22], which seems to suggest that HDGF plays an important role in the tumorigenesis and cancer progression.