COL6A1 and peripheral arterial disease: In addition, genes constituting a major portion of the vascular extracellular matrix were significantly up-regulated in advanced lesions, including COL1A1, COL3A1, COL1A2, COL5A1, COL6A1, COL6A3 and LAMB1, suggesting that these genes could be involved in the femoral artery occlusion in PAD.