PiRNAs and PIWI proteins as new biomarkers for diagnosis and treatment of liver cancer

Abstract

Hepatocellular carcinoma (HCC) is one of the most common malignancies and a major cause of cancer-related deaths worldwide due to the high mortality rate and unfavorable satisfaction treatment options available. However, a detailed understanding of the molecular mechanisms underlying liver cancer has not yet been established. piRNAs are RNA molecules with the estimated size of 26–31 nt binding to Piwi proteins. PIWI-interacting RNAs (piRNAs) are small non-coding RNAs (sncRNAs) that are composed of 24–32 nucleotides. These RNAs are responsible for epigenetic regulation and post-transcriptional regulation of gene expression. PIWI-piRNA pathway is the best characteristic of germ cells that have recently been identified in somatic tissues, including stem cells and cancer cells. Several studies have shown that this pathway plays an important role in individual cellular processes. Evidence is shown that abnormal piRNA expression is an important factor involved in cancer cell proliferation, apoptosis, invasion and migration in vitro and in vivo. Altered expression of piRNA in cancer is associated with clinical outcomes, highlighting the important role that they may serve as new diagnostic and prognostic biomarkers and as therapeutic targets for cancer treatment. Therefore, we have focused on PIWI proteins and piRNA functions and their effects on the progression of liver cancer.