Scientists have managed to produce a small-scale version of a human liver in the laboratory using stem cells.
The success increases hope that new transplant livers could be manufactured, although experts say that this is still many years away.
The team from Wake Forest University Baptist Medical Center presented its findings at at conference in Boston.
UK experts said it was an "exciting development" but it is not yet certain a fully-functioning liver is possible.
The demand for transplant livers far exceeds the number of available organs, and in recent years, research has focused on ways to use cell technology to support failing organs in the body, or even one day replace them.
Their building block is the stem cell, a "master cell" which can, in certain conditions, divide to produce different types of body tissue.
However, constructing a three-dimensional organ from stem cells is a difficult task.
BBC News
