Cancer Spread Between Identical Twins in the Womb, Scientists Find

Researchers at the Wellcome Sanger Institute documented an extremely rare case in which a tumor in one identical twin spread to the other through their shared placental blood supply. Both babies were delivered at 34 weeks and died shortly after birth; genomic analysis also revealed an unusual placenta made almost entirely of one twin's cells.

• Tumor began in one twin and spread to the other via the placenta
• Babies were delivered at 34 weeks and both died after birth
• The placenta was almost entirely made of the second twin's cells
• Findings were published in Nature Communications