PLK4 and glioblastoma: 5). Besides breast cancer, Plk4 has been found to be upregulated in most solid tumors, such as gastric, pancreatic, lung, melanoma, cervical, osteosarcoma and brain (neuroblastoma, glioblastoma, medulloblastoma) tumors, and associated with shortened patient survival in these tumors [18, 80, 81].