PVT1 and cancer: Moreover, a role as a sponge for tumor-suppressor miRNAs with oncogenic properties has been described for both PVT1 isoforms, even though the literature points on different miRNA entities, depending on cancer type, especially for circPVT1. Their pro-tumorigenic role is often attributed to their functional interaction with the MYC oncogene, localized about 54 Kb upstream PVT1. However, recent findings provided new insights on potential MYC-independent functions, especially for circPVT1, which will be addressed in the following sections.