A recent study on glioma cells showed that targeting and knocking out RECQL4 using the CRISPR/Cas9 technique could enhance the toxicity of temozolomide (TMZ) on glioma cells so that levels of DNA damage and apoptosis markers, including phospho-H2AX, PARP-1, and cleaved caspases 3 and 7, are significantly increased [98]. Here, PARP1 is linked to central nervous system cancer.