Importantly, collagen IV is the main components of basement membrane of colon mucosa in the lamina propria mucosae [100] and is highly expressed in the desmoplasia of CRC liver metastases patients [60], but type IV collagenases (MMP-2 and MMP-9) are significantly up-regulated in the basement membrane during CRC development, leading to collagen IV degradation [101]. This evidence concerns the gene MMP9 and colorectal carcinoma.