US researchers have successfully tested the method of mixing a woman's stem cells with her body fat to partly-regenerate breasts after partial masectomies, it was announced on Sunday.

Researchers from the Cytori Therapeutics company in San Diego announced the results of a study on 21 women in Japan, who underwent partial breast removals and, at the same time, had some of their stem cells and body fat removed, according to a company report. A year later, regenerated tissue and body fat was used as doctors re-engineered the lost breast tissue.

The company told cancer researchers meeting in San Antonio, Southern California that none of the 21 women have shown signs of cancer spreading or any tissue rejection for a year after their lumpectomies.

In a statement, Cytori said it isolated those stem cells with its Celution System using tissue taken from the women during their cancer operations. Because the women were injected with stem cells from their own bodies, there were no issues with tissue rejection.

The company said there was a "statistically significant improvement in average breast tissue thickness."

"This clinical series is an exciting, early development for women with breast cancer who undergo partial mastectomy," said the company's president Marc H. Hedrick.

Cytori said it will conduct two clinical studies in Europe by Cytori to further evaluate adipose-derived stem and regenerative cells.

Human fat is one of the body's richest and most accessible sources of regenerative cells, the company said, and include adult stem cells in addition to other important cell types that can improve volume retention and graft persistence, the company said.

The announcement is making national headlines. The Chicago Tribune quoted a plastic surgeon at the University of Chicago, Dr. David Song, as saying "there could definitely be promise here."

Cytori Therapeutics is developing its Celution System as a means of regenerative cell banking.

(Xinhua News Agency December 17, 2007)