Researchers in this study wanted to find better ways to detect whether breast cancer has spread (metastasized) or may come back after treatment. One challenge in cancer care is identifying patients who still have tiny amounts of cancer in the body—called micrometastatic disease—even when no tumors are visible. The researchers explored whether changes in DNA found in the blood could help solve this problem.
They focused on cell-free DNA, which is small fragments of DNA released into the bloodstream from cells, including cancer cells. Using a technique called whole-genome bisulfite sequencing, the researchers analyzed patterns of DNA methylation, which are chemical changes that affect how genes are turned on or off.
The study found that patients with metastatic breast cancer had distinct DNA methylation patterns compared to healthy individuals and patients who were cancer-free after treatment. Specifically, they identified widespread changes across the genome, including areas where DNA was either more or less methylated. They also discovered 21 specific regions (“hotspots”) that showed strong differences in metastatic cancer.
Overall, these findings suggest that analyzing DNA methylation in blood could help detect hidden cancer and identify patients at higher risk of recurrence.
