FN1 and neoplasm: This disparity in sensitivity of stiffness and CVF might be due to 1) the contribution of other ECM components than collagen such as fibronectin, proteoglycans, or glycosaminoglycans to tumor stiffness (47, 48), or 2), in vivo factors such as blood perfusion and vascular resistance (49) to which tomoelastography is sensitive (17).