An update of new targets for cancer treatment: vessels and matrix.

The identification and validation of targets for therapeutic drugs lies at the very heart of pharmacological research. Angiogenesis, or more specifically tumour initiated growth of new vessels, has been an active area of cancer research for several years. Indeed, there are currently more drugs in cancer clinical trials that are anti-angiogenics than those that fit into any other mechanistic category. Despite this, none has yet reached the clinic and there have been some setbacks along the way. Nevertheless, there remains a prevailing mood of optimism concerning the future for anti-angiogenic drugs. In addition, recent developments in direct targeting of drugs to existing tumour vessels has led to a resurgence of interest in this complimentary approach. The purpose of this article is to provide a brief overview of where we stand with anti-angiogenic therapy and to outline the recent advances in vascular targeting. For extensive reviews the reader is referred to Yancopoulos et al. [1], Ferrara and Alitalo [2] and Oehler and Bicknell [3].