Maternal screening could help prevent deadly forms of leukemia

A deadly form of leukemia may be stopped before it ever develops by introducing targeted maternal screening in the United States, according to new research. The national study, led by physician-scientists at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, found that a virus passed from mother to child-often decades before cancer appears-drives sharply higher disease rates in certain populations, pointing to a practical opportunity to prevent cases entirely.

Adult T-cell leukemia/lymphoma is rare, aggressive and often fatal, but it is also preventable. Its cause-human T-cell leukemia virus type 1, or HTLV-1-is typically transmitted early in life, most often through breastfeeding. Decades later, that early exposure can surface as a fast-moving cancer with few effective treatment options.

The new study led by Paulo Pinheiro, M.D., Ph.D., professor of cancer epidemiology at Sylvester, found that this largely overlooked virus is present in U.S. residents born in HTLV-1–endemic regions, particularly the Caribbean, and that maternal screening may be a potential prevention strategy.

"This is one of the few cancers where we understand the cause, the timeline and-most importantly-how to prevent it," said Pinheiro, lead author of the Sylvester study published in JAMA Oncology.

While most people infected with HTLV-1 will never develop cancer, for those who do, the result is adult T-cell leukemia/lymphoma (ATLL), a disease with a five-year survival rate below 25%.

Globally, ATLL follows a map drawn by HTLV-1, clustering in southwestern Japan, the Caribbean, parts of South America and Africa. Japan responded decades ago with nationwide maternal screening programs that dramatically reduced mother-to-child transmission. In the United States, no comparable effort exists.

That absence became the central question of Sylvester's national study.

Using an unusually broad lens-cancer registry data from all 50 U.S. states spanning nearly two decades-Pinheiro and colleagues identified more than 3,000 ATLL cases, making the analysis the most comprehensive of its kind in the country.

Pinheiro said what emerged was a stark pattern. ATLL incidence varied not only by race but also by birthplace. Among non-Hispanic Caribbean-born U.S. residents, incidence was more than 30 times higher than among people born in the U.S. or Canada. In some island-born populations, rates approached-and in certain analyses exceeded-those reported in historically endemic regions of Japan.

When we disaggregated by country of birth, the signal became impossible to ignore. Florida and New York stood out."

 Paulo Pinheiro, M.D., Ph.D., professor of cancer epidemiology at Sylvester

With one of the largest Caribbean-born populations in the country, Florida accounted for nearly half of all U.S. cases, alongside New York. Tens of thousands of infants have been born in Florida over the past two decades to mothers from HTLV-1–endemic regions, yet routine maternal screening is not part of U.S. prenatal care. Nationally, nearly one million children have been born in the United States since 2000 to mothers from HTLV-1 endemic regions. "Targeted maternal screening is not part of routine prenatal care," Pinheiro said.

The discovery reframed ATLL not as an unavoidable rarity but as a disease that could be stopped with early prevention.

Supporting the findings, "Maternal screening is where cancer prevention and women's health intersect most clearly for this disease," said study co-author Sophia George, Ph.D., Sylvester researcher and associate professor in the Division of Gynecological Oncology within the Department of Obstetrics and Gynecology at the Miller School.

The researchers also confronted a second problem hiding in plain sight: misclassification. Because HTLV-1 testing is not routine when patients present with T-cell lymphomas, ATLL is often coded instead as peripheral T-cell lymphoma not otherwise specified, or PTCL-NOS.

To test whether this diagnostic blind spot was masking the true burden of disease, the team conducted sensitivity analyses that redistributed excess PTCL-NOS cases likely to represent undiagnosed ATLL. The result was striking: ATLL incidence among Caribbean-born individuals nearly doubled.

In other words, the cancer was not just rare. It was underrecognized.

"If we do not identify HTLV-1 and ATLL correctly, we miss the opportunity to prevent a fatal cancer decades before it develops," Pinheiro said.

Survival data reinforced the urgency. Outcomes were poor across all groups but worst among Caribbean-born patients, reflecting late diagnosis, aggressive disease biology or gaps in access to specialized care.

ATLL is unusual among cancers because it is the only human cancer known to be caused by a retrovirus, its timeline is long and its prevention is proven. Interrupting mother-to-child transmission of HTLV-1 can effectively help eliminate lifetime risk of the disease, explained Sylvester physician-scientist who studies ATLL, Juan C. Ramos, M.D., senior author of the study and professor of Clinical Medicine in the Division of Hematology at the Miller School.

"Understanding how this cancer develops in patients with HTLV-1 infection gives us a chance to intervene much earlier-long before patients ever need treatment," said Ramos. "That's where translational research can have its greatest impact."

Japan's experience offers a real-world precedent. After decades of maternal screening and breastfeeding counseling, new ATLL diagnoses have begun to decline. The U.S., by contrast, continues to screen only blood donors-not pregnant women-even in high-risk populations.

The study's findings suggest a practical, targeted alternative. Rather than universal screening, which may not be cost-effective in low-prevalence populations, focused maternal screening based on country of birth could meaningfully reduce future cancer burden while minimizing unintended harm.

"The goal is to move the window of intervention upstream," Ramos said. "When we connect population data to biology, prevention becomes a realistic part of cancer care."