PARP1 and glioma: Subsequent studies unveiled a significant decrease in the mRNA (Fig. 9F) and protein (Fig. 9G) expression levels of Cyclin A2, Cyclin B2, and TOP2A within koORC6 P1 glioma xenograft tissues, where elevated levels of cleaved-caspase-3, cleaved-caspase-9, and cleaved-PARP-1 were detected (Fig. 9H), indicating apoptosis activation.