ACAN and neoplasm: Several matrix metalloproteinases (MMPs) were up-regulated in tumour samples, namely MMP12 (5.1-fold), MMP14 (2.3-fold) and MMP2 (2.2-fold), which cleave elastin (and insulin), collagen (and other extracellular proteins, such as aggrecan) and certain collagens (and gelatin), respectively.