DNA segments point to aggressive colorectal disease
According to a new study, the tumors of patients with a family history of colorectal cancer often carry a molecular sign that the cancer could be life threatening and may necessitate aggressive treatment.
The study finding suggests that colorectal cancer patients could, in the future, receive more intense therapies and a family cancer-risk assessment for their relatives. Furthermore, to catch the disease at the earliest possible stage, such patients’ relatives could be eligible for more frequent colonoscopies.
The newly discovered molecular sign occurs in DNA segments. These sections, called long interspersed nucleotide element 1 (LINE-1), constitute about 17% of our DNA. Methyl groups usually cover LINE-1.
In the current study, reported in the Journal of the National Cancer Institute, researchers led by Shuji Ogino, MD, PhD, MS, and Charles Fuchs, MD, MPH, from Dana-Farber Cancer Institute, found that for many colorectal cancer patients with a family history of the disease, the LINE-1 in their tumor cells was hypomethylated.
In order to gain definitive insights, investigators took a large-scale “prospective” approach and used data from the Nurses’ Health Study and the Health Professionals Follow-up Study, which includes the health of tens of thousands of people over many decades. Ogino, Fuchs, and colleagues sought to determine if participants with a family history of colorectal cancer tended to develop colorectal cancer with low-level methylation of LINE-1.
“We found that, compared to individuals without a family history of colorectal cancer, people who had first-degree relatives affected with the disease indeed had a higher risk of developing colorectal cancer with hypomethylated LINE-1,” says Ogino, the paper’s first author. “Because this variety of colorectal cancer can quickly become dangerous, testing colorectal cancer patients for tumor LINE-1 hypomethylation may offer a valuable way of identifying those in greatest need of aggressive treatment. Such testing could also help identify patients whose relatives may be at increased risk for the aggressive form of the disease.”
Source: Dana-Farber Cancer Institute.