Genomic tracing reconstructs a rare cancer’s spread between twins before birth
Published in Bioinformatics, Diseases!, Journals.
Published October 17, 2026.
A genomic investigation has reconstructed how a rare soft-tissue cancer began in one identical twin and crossed the placenta to the other before birth. The study appeared in Nature Communications on October 6, 2026, and received renewed coverage on October 16.
Researchers from the Wellcome Sanger Institute, Great Ormond Street Hospital and collaborating institutions compared whole-genome sequences from tumours, healthy tissues and the placenta. Genetic differences accumulated during development allowed them to reconstruct relationships between cell populations. Their analysis supported a single origin in one twin followed by one transmission event, rather than two independently arising cancers.
The investigation also revealed unequal contributions of early embryonic cell lineages to the twins and their placenta. These findings raise questions about conventional models of identical-twin development and illustrate how cancer genomics can illuminate events occurring before birth.
This is a reconstruction involving one pair of twins, not a population study or a treatment trial. It cannot establish how frequently such transmission occurs, and the developmental findings require testing in additional families.
Sources: Walkowiak and colleagues, Nature Communications, October 6, 2026; Medical Xpress coverage, October 16, 2026.