Sylvester Comprehensive Cancer Center Identifies a Screening Gap to Prevent a Type of Leukemia in the U.S.

What if a deadly cancer could be stopped before it ever takes hold, not with a breakthrough drug or years of treatment but by preventing an infection passed quietly from mother to child?

Adult T-cell leukemia/lymphoma (ATLL) is one of the few cancers for which this is true. The disease 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.

A team of researchers at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, and led by Paulo Pinheiro, M.D., Ph.D., professor of epidemiology and population health sciences at the Miller School, identified that this largely overlooked virus is present in U.S. residents born in HTLV-1–endemic regions, particularly the Caribbean. Maternal screening may be a potential prevention strategy. The findings have important implications for South Florida.

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

Most people infected with HTLV-1 will never develop cancer. For those who do, the result is adult T-cell leukemia/lymphoma, 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.

Discovery: Seeing What the Data Was Hiding

To answer that question, the research team turned to cancer registry data from all 50 U.S. states spanning nearly two decades. In total, more than 3,000 ATLL cases were identified, making the analysis the most comprehensive of its kind in the country.

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,” Dr. Pinheiro said. “Florida and New York stood out.”

With one of the largest Caribbean-born populations in the country, the state of Florida accounted for nearly half of all U.S. cases. 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 1 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,” Dr. Pinheiro said.

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

“Maternal screening is where cancer prevention and women’s health intersect most clearly for this disease,” said study co-author Sophia George, Ph.D., associate professor in the Miller School’s Department of Obstetrics, Gynecology and Reproductive Sciences and a member of Sylvester Comprehensive Cancer Center.

Validation: Correcting a Diagnostic Blind Spot

The researchers also confronted the problem of misclassification. HTLV-1 testing is not routine when patients present with T-cell lymphomas, so 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,” Dr. 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.

Impact: A Roadmap for Prevention

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 a Sylvester physician-scientist who studies ATLL.

“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 Juan Ramos, M.D., senior author of the study and professor of hematology at the Miller School. “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,” Dr. Ramos said. “When we connect population data to biology, prevention becomes a realistic part of cancer care.”