Scientists have spent much time and energy mapping the many DNA misspellings that can transform healthy cells into cancerous ones. But recently it has become increasingly clear that changes to the DNA sequence itself are not the only culprits. Cancer can also be driven by epigenetic changes to DNA—modifications to chemical marks on the genome don’t alter the sequence of the DNA molecule, but act to influence gene activity. A prime example of this can been seen in glioblastoma, a rare and deadly form of brain cancer that strikes about 12,000 Americans each year.
In fact, an NIH-funded research team recently published in Nature Communications the most complete portrait to date of the epigenetic patterns characteristic of the glioblastoma genome . Among their findings were patterns associated with how long patients survived after the cancer was detected. While far more research is needed, the findings highlight the potential of epigenetic information to help doctors devise more precise ways of diagnosing, treating, and perhaps even preventing glioblastoma and many other forms of cancer.
Earlier studies had suggested that glioblastoma comes with widespread epigenetic changes to DNA. However, the picture was far from complete, focusing only on the most common and well-studied DNA modification, known as 5-methylcytosine (5-mC). The new study, led by Kevin Johnson and Brock Christensen at the Geisel School of Medicine at Dartmouth College, Lebanon, NH, broke new ground by applying laboratory  and statistical approaches  that now make it possible to distinguish between 5-mC and another chemical mark called 5-hydroxymethylcytosine (5-hmC) to tumor samples.