Anti-angiogenesis and metastasis: a tumour and stromal cell alliance.

Tumour progression requires the activation of a tumour and stromal cell-driven angiogenic programme, and the targeting of this process demonstrates an impact on tumour growth and progression. The results of preclinical studies have demonstrated a proinvasive/metastatic effect of antiangiogenic treatments with recent evidence supporting a contribution of the stroma to tumour aggressiveness and the short-term effects of antivascular endothelial growth factor therapy. Furthermore, hypoxia-dependent and -independent factors are considered as driving forces for tumour cell escape by altering both the tumour cells themselves and the stroma. This tumour-stromal cell alliance should be taken into consideration for the development of innovative therapeutic options targeting both tumour components to improve clinical benefits for cancer patients.