PCNA and central nervous system cancer: For instance, miR‐451 is a tumour suppressor that acts on inhibitor of NF‐κB kinase subunit β (IKKβ) to activate the NF‐κB signalling pathway and reduce MMP9, MMP2, proliferating cell nuclear antigen (PCNA), cyclin D1, IKKβ and phosphorylated p65 expression, so as to weaken the proliferation and invasion of glioma cells,48 whereas Gheidari et al.49reported that miR‐489‐3p could activate the PI3K/AKT signalling pathway under the action of brain‐derived neurotrophic factor and inhibit the invasion of GBM cells.