New challenges in hepatocellular carcinoma: A role for PIWI-interacting RNAs?

Figure 1 Schematic diagrams of the biosynthesis of PIWI-interacting RNAs. A and B: The primary (A) and secondary (B) cycles (also known as the “ping-pong cycle”) are shown. Note that the PIWI-interacting RNA (piRNA) precursor that triggers primary biosynthesis can be either a sense or an anti-sense piRNA precursor. Image created by Biorender. Zuc: Zucchini; piRNA: PIWI-interacting RNA; Nbr: Nibbler.