PARP1 and ovarian cancer: In contrast, growth arrest-specific 5 (GAS5) is an lncRNA that exerts a tumor-suppressive function in ovarian cancer through sponging miRNAs such as miR-21 [12], and by facilitating the E2F4-mediated transcriptional repression of poly (ADP-ribose) polymerase 1 (PARP1) [14].