We reviewed data from the most promising candidate biomarkers of BRCAness in GBM, namely mutate isocitrate dehydrogenases 1 and 2 (IDH1/2), EGFR mutated variant (EGFR vIII), phosphatase and tensin homolog (PTEN), MYC oncogene, and the estrogen receptors beta (ERβ). The gene discussed is PTEN; the disease is glioblastoma.