Biomarkers that help researchers detect cancer (lat. Carcinoma) earlier was developed by scientists from Northwestern University. The main mission of the research is to identify biomarkers of the interplay of genes and environment in cancer. Precision medicine considers each individual’s genetic and environmental factors to determine treatment strategies. Also known as personalized medicine, this field rejects the idea that one drug or treatment works for all patients. Lifang Hou, a professor of preventive medicine and chief of cancer epidemiology and prevention at the Feinberg School of Medicine, focused on cancer biomarkers - biological indicators of the disease - in blood. Blood-based biomarkers, she says, will allow for simpler, lower-cost tests that can be deployed in physicians’ offices during routine check-ups. Equally important: These biomarkers are indisputable.

Changes in telomere length may be one such biomarker. Telomeres are the protective end caps at each of our chromosomes. Their telomeres typically get shorter as we age, but environmental factors - diet, smoking, exposure to pesticides, air pollution and heavy metals - can also contribute to premature shortening. And, Lifang Hou has found, changes in telomere length over time may be an indicator of oncoming cancer.

In a retrospective study, Lifang Hou and her team looked at telomere length over a 13-year period in almost 800 people, 135 of whom eventually received a cancer diagnosis. Telomeres for everyone shortened each year for several years, but among those who were eventually diagnosed with cancer, telomeres shortened much faster - appearing 15 years older, in some cases - than those who were not subsequently diagnosed with cancer. And even more surprisingly, the telomeres of people who eventually received a cancer diagnosis stopped shortening about 3-4 years before their diagnosis, while the telomeres of people who were not diagnosed with cancer continued to shorten.

This research is the first reported trajectory of telomere changes over many years in people who eventually develop cancer. It is also believed to be the first to look at telomere length at more than one point before diagnosis. Lifang Hou says this is significant because cancer treatment itself can change telomere length, making it difficult to know to what extent telomere length has been impacted by cancer itself. Lifang Hou’s team is now expanding this telomere work on a grand scale. Collaborating with well-known scientists across the globe, Lifang Hou’s team is studying large population cohorts and using deep sequencing data to examine telomere changes with an unprecedented level of detail.

Lifang Hou envisions a day when routine, annual lab testing measures a patient’s telomere length alongside conventional metrics like blood cell count and cholesterol level. If their telomere length has changed significantly from one year to the next, the doctor would follow up to see what’s changed in the patient’s life ­- their diet, exercise routine, stress level, etc. Lifang Hou hopes physicians will also be able to use blood-based telomere length for 'risk stratificiation', identifying those who would benefit from more invasive, costly screenings like colonoscopies. Lifang Hou is committed to studying multiple biomarkers, including telomere length, because she understands the complexity of cancer. Telomeres can’t tell the whole story - genes and environment are far too vast and variable - but they could be a valuable preventive tool.