In a recent study sequencing the exomes of 23 low-grade gliomas and their recurrences, in 43 % of cases, at least half of the mutations in the initial tumor were undetected at recurrence, including mutations considered to be driver mutations such as TP53 and ATRX. These findings suggest that recurrent tumors are often seeded by cells derived from the initial tumor at a very early stage of their evolution [55]. The gene discussed is ATRX; the disease is glioma.