A recent study by scientists from the Northwestern University Feinberg School of Medicine and Harvard University shows how the shifting length of blood telomeres, which are the defensive covers at the end of DNA strands, may predict cancer development some 13 years prior to actual diagnosis.
The scientists observed that blood telomeres—sequences of DNA at the end of a chromosome that protect them from deterioration—age quicker on future cancer patients compared to healthy individuals. This is indicated in the rapid length reduction of the telomeres, which then stop maturing for a couple of years in the period leading to the diagnosis of cancer.
"Understanding this pattern of telomere growth may mean it can be a predictive biomarker for cancer," said Dr. Lifang Hou, an associate professor of preventive medicine at the Feinberg School of Medicine and the lead author of the study.
The distinguishing pattern exhibits a fast reduction in the blood telomeres' length, followed by three to four years of pause during which no significant changes in the length are recorded.
The scientists took various telomere measurements across a 13-year period in 792 persons. A total of 135 participants were eventually diagnosed with cancer, including leukemia, lung, skin and prostate cancer.
Telomeres reduce their length during cell division, and this process continues as humans age.
However, cancer cells also grow and divide very fast, so scientists once assumed these cells would also self-destruct since their telomeres would shorten. The study suggests that cancer cells have instead established a process to halt the reduction in the telomeres' length.
Hou said that if the process behind cancer cells escaping normal cell division and telomere reduction is examined more closely, then it is possible to develop treatments that can cause cancer cells to self-destruct without damaging healthy cells.
This study, published in the journal Ebiomedicine, hopes to analyze changes in telomere length in the years prior to the diagnosis of cancer and before the initiation of radiation treatment. It is known that treatments for cancer affect telomere length.
However, it should be noted that insurance companies warned that if cancer detection through this type of blood testing will be successful in forecasting cancer development, it could push up policy premiums for those people who are likely to develop the disease later on.
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