There are many documented cases of functionally relevant co-occurring oncogenic mutations, such as the concomitant inactivation of TP53 and RB1 [17], co-deletion of CDKN2A and CDKN2B [18], co-amplification of MDM2 and CDK4 [19, 20], 1p/19q co-deletion in glioma [21], MYC amplification and TP53 mutations [22], or activating alterations in KRAS and BRAF [5]. The gene discussed is TP53; the disease is central nervous system cancer.