As the population continues to age, the need for biological measures of age and more precise screening tests for age-related diseases is becoming increasingly urgent.  Epigenetics serves as an intersection between genetic and environmental risk factors for aging processes and age-related diseases, holding great promise for constructing biological age measures that will provide clinical diagnostic tools for aging-related diseases such as cancer.

Now, a study from researchers at Northwestern University Feinberg shows that when a person’s biological, or epigenetic, age is older than their chronological age, they’re at increased risk for getting and dying of cancer.  The team state that the bigger the difference between the two ages, the higher your risk of dying of cancer and that the discrepancy between the two ages appears to be a promising tool that could be used to develop an early detection blood test for cancer.  The opensource study is published in the journal EBioMedicine.

Previous studies show that epigenetic age is a recently developed algorithm that uses DNA methylation measurements to describe biological age at the level of human tissues, cells, and organs.  It has been shown that epigenetic age does not always parallel chronological age, particularly in tumour samples.  As the methods for measuring epigenetic age incorporate pathways related to both cancer development and aging in general, it it has long been hypothesized that this difference in epigenetic and chronological age can be a predictive biomarker for cancer risk, metastasis, and mortality.  Recent studies show that people who are healthy have a very small difference between their epigenetic/biological age and chronological age.  The current study shows that people who develop cancer have a large difference and people who die from cancer have a difference even larger than that.

The current study was a longitudinal design with multiple blood samples collected from 1999 to 2013. The group used 834 blood samples collected from 442 participants who were free of cancer at the time of the blood draw.  Results show that for each one-year increase in the discrepancy between chronological and epigenetic ages, there was a 6% increased risk of getting cancer within three years and a 17% increased risk of cancer death within five years. Data findings show those who will develop cancer have an epigenetic age about six months older than their chronological age; those who will die of cancer are 2.2 years older on average.

The group state that they calculated the patient’s epigenetic age using an algorithm measuring 71 blood DNA methylation markers that could be modified by a person’s environment, including environmental chemicals, obesity, exercise and diet.  Results show that the multiple samples, which showed changing epigenetic age, allowed for more precise measurements of epigenetic age and its relationship to cancer risk.  The lab note that other studies have looked at blood samples collected only at a single time point, however, theirs is the first study to link the discrepancy between epigenetic age and chronological age with both cancer development and cancer death using multiple blood samples collected over time.

The team surmise their data suggests that the global medical community should focus on the epigenetic-chronological age discrepancy for its potential to show a big picture snapshot of human health and disease at a molecular level.  For the future, the researchers state they are now are investigating whether individuals can lower their epigenetic age through lifestyle improvements such as increasing exercise and having a healthier diet.

Source: Northwestern University