DKK3 and neoplasm: Among the growth factors are Dickkopf-related protein 3 (DKK3)23, also known as a tumor suppressor (“reduced expression in carcinoma REIC”)24–26; melanoma-derived growth regulatory protein (MIA)27, a factor that inhibits melanoma cell growth and is also known as “cartilage-derived retinoic acid-sensitive protein (CD-RAP)” with a role in cartilage differentiation28; and neutrophil gelatinase-associated lipocalin (NGAL)29, a factor that promotes renal epithelial cell differentiation.