Recent advances in the non-invasive assessment of fibrosis using biomarkers.

Fibrosis can occur in most organs and is characterised by excessive and progressive extracellular matrix deposition and destruction of normal tissue architecture and function. In many cases treatment options are limited. Fibrotic diseases are therefore associated with high morbidity and mortality. Tissue biopsies remain a key part of diagnosing fibrosis; however, due to their invasive nature, tissue biopsies are unsuitable for monitoring disease progression. In some cases, tissue biopsies carry an unacceptable risk of mortality to the patient. Furthermore, assessing fibrosis via tissue biopsy is severely limited by the heterogenetic nature of fibrotic diseases and suffers from both sampling bias and observer variation/bias. The search for less invasive methods of diagnosing and monitoring fibrosis has led to the identification of many new biomarkers, many of which can be measured in serum in a so-called 'liquid biopsy' or can be imaged using state-of-the-art imaging modalities. These approaches have the potential to dramatically improve the diagnosis and monitoring of disease, and improve the design of clinical trials in to novel fibrotic therapies. This review summarises some of the recent advances in identifying novel biomarkers to diagnose and monitor fibrosis non-invasively.