Further research on matched primary and recurrent glioblastomas revealed that genomic profiles of recurrent glioblastomas differ significantly from those of the initial tumors, with one study finding that p53 pathway alterations are predictive of a high number of subclonal mutations [41] and another concluding that re‐biopsy and re‐profiling are needed for clinical decision‐making, especially in patients with distant recurrent tumors, which had even fewer mutations in common with the primary tumor than locally recurrent tumors [42]. This evidence concerns the gene TP53 and glioblastoma.