Background: In recent years, several anti-angiogenic drugs have been developed
and their addition to standard treatment has been associated with clinical benefits. However,
the response to anti-angiogenic therapy is characterized by considerable variability. In this
context, the development of dynamic non-invasive biomarkers would be helpful to elucidate
the emergence of anti-angiogenic resistance as well as to correctly address the treatment.
Objectives: The purpose of this review is to describe current reports on circulating diagnostic
and prognostic biomarkers related to angiogenesis. We further discuss how this non-invasive
strategy could improve the monitoring of tumor treatment and help clinical strategy.
Results: We discuss the latest evidence in the literature regarding circulating anti-angiogenic
markers. Besides growth factor proteins, different circulating miRNAs could exert a pro- or
anti-angiogenic activity so as to represent suitable candidates for a non-invasive strategy. Recent
reports indicate that tumor-derived exosomes, which are small membrane vesicles abundant
in biological fluids, also have an impact on vascular remodeling.
Conclusion: Numerous circulating biomarkers related to angiogenesis have been recently
identified. Their use will allow identifying patients who are more likely to benefit from a specific
anti-angiogenic treatment, as well as detecting those who will develop resistance and/or
adverse effects. Nonetheless, further studies are required to elucidate the role of these biomarkers
in clinical settings.