Researchers Identified Cancer Transfer Between Twins
A study confirmed that cancer cells spread from one twin to another through the shared placenta.
Updated on Oct. 9, 2026 in Cancer
A medical study published in Nature Communications identified a rare case of cancer transmission between twins in utero. Scientists discovered that undifferentiated sarcomas originated in one fetus and spread to the other via the shared placenta.
Why it matters
Understanding how cancer spreads in utero provides critical insights into fetal development and rare childhood malignancies. This research highlights the complex cellular exchange that occurs in twins sharing a placenta.
Researchers sequenced 33 samples, including tumor and placental tissues, to confirm the transmission. Data showed that 75 percent of cells in a spleen sample from one twin originated from the other.
The players
Wellcome Sanger Institute
This is a genomics research center that provided the genetic sequencing expertise used to trace the cellular family trees of the twins.
Great Ormond Street Hospital
This clinical research hospital participated in the study of the rare pediatric cancer cases.
University of Cambridge
This academic institution collaborated on the research project investigating the transmission of sarcomas.
The details
Genetic analysis revealed that the twins' undifferentiated sarcomas contained a shared fusion of MN1 and ZNF341 genes, confirming a single origin point. By mapping accumulated DNA mutations, researchers determined the cancer began in one twin during the first trimester and transferred during the late second trimester.
Timeline
The cancer likely originated in one twin at the end of the first trimester.
Transmission to the second twin occurred during the late second trimester.
A facial mass was detected in one twin during a fetal MRI at 33 weeks of gestation.
Both sisters were diagnosed with tumors at birth.
The Big Picture
This finding extends the body of knowledge established by the Nature Communications study on twin cancer transmission by providing a detailed genomic map of in utero cellular migration. It marks a departure from traditional hypotheses regarding the independent development of twin tumors.
This study advances the understanding of rare pediatric sarcomas and informs how clinicians screen for congenital masses during pregnancy. It provides diagnostic frameworks for identifying and treating complex tumor cases in twins.
The takeaway
This case underscores the profound interconnectedness of twins who share a placenta during development. It serves as a reminder of how genomic sequencing is increasingly used to decode rare and complex pediatric medical mysteries.
Further reading
For more information on similar medical discoveries, visit the Cancer section.
