The angiogenic process as a therapeutic target in cancer.

Angiogenesis has emerged as a critical process for tumour progression. Identifying key pathways involved in the regulation and promotion of angiogenesis has resulted in the development of numerous approaches targeting pro-angiogenic signalling pathways. The most prominent and characterised pro-angiogenic pathway is the vascular endothelial growth factor signalling pathway. This review will describe several inhibitors of angiogenesis currently in clinical trial and their various targets. Targeting pro-angiogenic pathways has improved outcome for many patients, however, the emerging problems with drug resistance with clinically approved angiogenic inhibitors will also be discussed in this review. It is hoped that identifying the causes of tumour re-growth and disease progression following treatment will enable future anti-angiogenic therapies to circumvent resistance.