TNF and neoplasm: This phenomenon can be related to the capability of TNF to reduce the barriers that limit drug penetration in tumor tissues, such as those related to the endothelial barrier function and to the high interstitial pressure, thereby leading to an increase of the convective transport of drugs through the tumor vasculature wall, at least in those areas that are poorly perfused and characterized by low permeability [9,33,34,35,36,37,38,39,40].