The Clock That Ticks Inside Cells
A forensic examiner arrives at a crime scene and lifts fingerprints. Epigenetic clocks work the same way: from chemical marks on DNA they determine how much a cell has aged. A tumor leaves its own "fingerprints," and almost always they point to decrepitude.
The researchers took 5528 samples from the TCGA database, which holds DNA methylation data for eight cancer types.