Embryonic stem cells and cancer formation

One of the major arguments raised by opponents of Australia's embryonic stem (ES) cell research bill, debated in the Senate recently, was the fear that when transplanted into an animal, ES cells have a substantial tendency to form teratomas, a type of tumour.

Now a team from the University of NSW, headed by leading proponent of ES cell research Professor Bernie Tuch, has shown that placing the cells within microcapsules prevents the formation of tumours when transplanted into lab animals.

Tuch and his team at the Diabetes Transplant Unit at the Prince of Wales Hospital are currently conducting clinical trials in diabetes patients using the encapsulation technology, this time to transplant insulin-producing cells isolated from donor humans without the use of anti-rejection drugs.

The capsules are made of alginate, an extract of seaweed, which are subject to an air-droplet process to form bubbles, in which the ES cells are inserted. The team's previous results show that the capsules allow the proliferation and differentiation of ES cells.

The data describing the new experiments was published this week in the journal Transplantation.

"Whilst embryonic stem cells have great potential to deliver therapies for disorders, such as diabetes, a fear has been that they will form tumours because of the presence of undifferentiated cells," Tuch said. "Our breakthrough removes what could have been a stumbling block to this vital research."

He said the passing of the bill through the Senate last week was extremely encouraging for further research.

For more information, see "Here we go again: what next for stem cells?" in Australian Life Scientist Sept/Oct 2006.