Growth Factors as Targets in Tumor Therapy

Abstract

Sustained growth of solid tumors and their metastasis requires paracrine signals between the tumor cells and the normal surrounding host tissue. One crucial function of these signals is to recruit endothelial cells and thus new blood vessels for the nourishment of the expanding tumor mass. In addition, the newly recruited blood vessels serve as routes for metastasis of the primary tumor. The proliferation and migration of endothelial cells in the vicinity of progressing tumors contrasts with a low turn-over rate of endothelial cells in the healthy adult. The only physiologic exception to this rule is the female reproductive cycle. Based on the selective angiogenesis in tumors in contrast to normal tissues, a blockade of this process should be feasible with few adverse effects. We present data on angiogenesis factor gene expression in tumors and discuss different methods of targeting these gene products. Furthermore, we discuss the potential to combine conventional cytotoxic treatments with this new therapeutic approach.