Recurrent tumors often develop a set of genetic mutations that are markedly different from the original tumor, reports an international group of scientists who analyzed the genomes of 23 low-grade gliomas and recurrences of those malignancies (Johnson BE et al. Science. 2014;343:189-193).
In 43% of cases, at least half of the mutations in the initial tumor were undetected at recurrence. The investigators also found that recurrent tumors from patients who were treated with temozolomide, an alkylating agent that inhibits DNA replication, were hypermutated compared with recurrent gliomas from patients not treated with temozolomide. Many of the mutations occurred in genes involved with the RB and AKT-mTOR cell signaling pathways, which are associated with high-grade gliomas and are known cancer drivers.
Hampton T. New Mutations May Develop in Recurrent Tumors. JAMA. 2014;311(5):456. doi:10.1001/jama.2014.26