MAY 04, 2015

Biomarker in Blood Test May Have Early Cancer Answer

WRITTEN BY: Ilene Schneider
A distinct pattern in a blood test could predict cancer years before an actual diagnosis, according to a new study by Northwestern University researchers published in the journal, EBioMedicine. The National Institutes of Health funded the study.

The researchers working with lead author Lifang Hou, professor of preventive medicine at Northwestern University Feinberg School of Medicine, and Andrea Baccarelli, from Harvard University, the study's senior author, described a pattern of rapid shortening of blood telomeres followed by stabilization three or four years before the diagnosis of cancer. This scenario could lead to a new biomarker that would predict the development of cancer using a blood test.

The study represents the first reported trajectory of changes in telomeres - the end caps on DNA strands that protect the chromosomes - over the years in people developing cancer. Some people liken telomeres to the plastic tips at the end of shoelaces that keep them from becoming frayed.

According to www.tasciences.com/what-is-a-telomere/, telomeres are an essential part of human cells that affect how cells age. Telomere (tel-uh-meer) comes from the Greek telos (end) and meros (part). Without telomeres, DNA strands become damaged, and cells are unable to do their job.

Researchers have attempted to understand how blood cell telomeres were affected in people developing cancer. In previous studies results have shown telomeres to be shorter, longer or not affected at all. The new study showed the reasons for inconsistency.

In obtaining multiple measurements of telomeres over a 13-year period in 792 people, 135 of whom were eventually diagnosed with different types of cancer, the scientists initially discovered that telomeres aged much faster in people who were developing but not yet diagnosed with cancer. It appeared that telomeres in people developing cancer were as much as 15 years chronologically older than those of people who were not developing the disease, but then the scientists discovered that the accelerated aging process stopped three to four years before the cancer diagnosis.

According to Hou, "Understanding this pattern of telomere growth may mean it can be a predictive biomarker for cancer. Because we saw a strong relationship in the pattern across a wide variety of cancers, with the right testing these procedures could be used to eventually diagnose a wide variety of cancers."

He added, "This likely explains why the previous studies have been so inconsistent. We saw the inflection point at which rapid telomere shortening stabilizes. We found cancer has hijacked the telomere shortening in order to flourish in the body."

This is the first time a study had looked at telomere length at more than one time point before diagnosis. Cancer treatment can shorten telomeres, after which it is uncertain whether the cancer or the treatment has affected their length.

Every time a cell divides, telomeres get shorter. The older a person is, the more times each cell in his or her body has divided and the shorter the telomeres. Cancer cells divide and grow rapidly, making scientists think that the cell would get short enough to self-destruct. However, scientists found that cancer finds a way to stop that process.

When scientists learn how cancer attacks the cell, they may be able to develop treatments that cause cancer cells to self-destruct without harming healthy cells, Hou concluded.

Source: Northwestern University

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