MicroRNA signatures as predictive biomarkers in transarterial chemoembolization‐treated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. Unfortunately, many patients are diagnosed at a late stage with a delay in the optimal timing for tumor resection. Transarterial chemoembolization (TACE) is currently considered the standard of care for patients with unresectable HCC Barcelona system class B classification. However, the treatment response of HCC patients to TACE varies widely, and there is no reliable marker for predicting a patient's response to TACE. Thus, the identification of patients who are sensitive or resistant to TACE is important for individualized therapy. Recently, our understanding of cancer cell biology has progressed enormously. Much of this progress has been driven by technological advances enabling previously unachievable studies to be performed and yield a constantly evolving picture of the regulatory role of noncoding RNAs (ncRNAs) in tumor biology. MicroRNAs (miRNAs) are a class of ncRNA molecules that regulate nearly one‐third of all protein‐coding RNAs. The existing literature indicates that the deregulation of miRNAs can contribute to tumorigenesis and metastasis in multiple cancers, including HCC, via the control of cell proliferation, apoptosis, invasion, or metastasis. Analysis and evaluation of this type of regulatory RNA could shed new light on the behavior of many cancers and provide new diagnostic and prognostic biomarkers as well as pharmacological targets for novel treatment strategies. To this end, this review highlights the expression and functional roles of miRNAs in TACE‐treated HCC and explores the potential applications of miRNAs as diagnostic markers and therapeutic targets.