Researchers Trace the Origin of Blood Cancer to Early Childhood, Decades before Diagnosis

WASHINGTON, Dec. 8, 2020 /PRNewswire/ -- Genetic mutations linked with cancer can occur during childhood or even before birth and proliferate in the body for many years before causing cancer symptoms, according to a new study. The study, which traced the genetic origins of a blood cancer in 10 individuals, suggests there may be untapped opportunities to detect cancer warning signs much earlier and potentially intervene to prevent or slow cancer development.

"Our preliminary findings show these cancer driver mutations were often acquired in childhood, many decades before the cancer diagnosis," said senior study author Jyoti Nangalia, MD, of the Wellcome Sanger Institute and University of Cambridge. "Our results finally answer the common question posed by patients, 'How long has this cancer been growing?' as we were able to study how these particular cancers developed over the entire lifetime of individual patients."

The researchers analyzed bone marrow and blood samples from 10 people with Philadelphia-negative myeloproliferative neoplasms, a type of cancer that causes stem cells in the bone marrow to produce too many blood cells. In the majority of patients, this cancer is driven by a genetic mutation called JAK2^V617F. By assessing JAK2^V617F, other cancer-linked mutations and hundreds of thousands of other mutations that a person naturally acquires throughout life, the researchers were able to trace the ancestry of different blood cells and estimate the time at which each patient acquired JAK2^V617F and other important mutations.

They determined that, in these 10 patients, the first cancer-linked mutations emerged as early as a few weeks after the start of life and up to the first decade of childhood despite clinical disease presenting many decades later in life.

"We were not expecting this," said Dr. Nangalia. "In fact, in one patient, the JAK2 mutation was acquired more than 50 years before their diagnosis."

While it is often assumed that most cancers are diagnosed within a few years of their emergence, the findings point to a more gradual, lifelong process in which a single cell acquires a cancer-linked mutation early in life and then slowly grows over decades, ultimately leading to cancer.

"Some of these cancer-linked mutations are found in healthy individuals as we get older, suggesting that aging causes them," said Dr. Nangalia. "However, aging per se doesn't drive such growth – it simply takes a long time for the clones to grow." Sometimes, the growing clones pick up additional cancer-linked mutations along the way, accelerating their growth, researchers found.

"For these patients, we calculated how many of these cancer clones would have been present in the past, and our results suggest that these clones may have been detectable up to 10 to 40 years before diagnosis," said Dr. Nangalia. "In addition to detecting the mutations, the rate at which the mutated clones grew was also very important in determining whether, and when, cancer develops." The findings suggest that genetic testing could help identify people at risk for cancer much earlier than current methods allow, according to researchers.

The next steps would be to understand the factors that influence the different rates of cancer growth and determine whether there could be ways to intervene and slow the growth of cells with cancer-linked mutations. The researchers say their method for pinpointing the origin of this blood cancer could also be applied to other mutations and other blood cancers. "Understanding the timelines of development of different cancers is critical for efforts aimed at early cancer detection and prevention," said Dr. Nangalia.

Jyoti Nangalia, MBBChir, Wellcome Sanger Institute and University of Cambridge, will present this study during the Late-Breaking Abstracts session on Tuesday, December 8 at 7:00 a.m. Pacific time on the ASH annual meeting virtual platform.

For the complete annual meeting program and abstracts, visit www.hematology.org/annual-meeting. Follow ASH and #ASH20 on Twitter, Instagram, LinkedIn, and Facebook for the most up-to-date information about the 2020 ASH Annual Meeting.

The American Society of Hematology (ASH) (www.hematology.org) is the world's largest professional society of hematologists dedicated to furthering the understanding, diagnosis, treatment, and prevention of disorders affecting the blood. For more than 60 years, the Society has led the development of hematology as a discipline by promoting research, patient care, education, training, and advocacy in hematology. ASH publishes Blood (www.bloodjournal.org), the most cited peer-reviewed publication in the field, and Blood Advances (www.bloodadvances.org), an online, peer-reviewed open-access journal.

SOURCE American Society of Hematology

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