Scientists have for the first time grown a complex, fully functional organ from scratch in a living animal by transplanting cells that were originally created in a laboratory.
British scientists produced a working thymus, a vital immune system "nerve centre" located near the heart.
In future the technique, so far only tested on mice, could be used to provide replacement organs for people with weakened immune systems, scientists believe.
But it might be another 10 years before such a treatment is shown to be effective and safe enough for human patients.
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Pro-Leave campaigner Boris Johnson has responded in a politely worded letter to Jean-Claude Juncker's invitation to "come back to Brussels".
The Friends star had reportedly not seen her mother for several years following a feud - but reconnected with her shortly before she died.
A deal is believed to have been reached with official confirmation likely on Friday.