Young cancer patients left infertile by their treatment have been given new hope of having children as scientists announce they have produced the first human embryo from frozen ovarian tissue.

Researchers at the New York Presbyterian Hospi-tal/Weill Cornell Medical Center in the United States restored the fertility of a 36-year-old woman who had suffered from breast cancer by transplanting previously frozen ovarian tissue beneath the skin of her abdomen.

Three months after the transplant, her fertility was restored. The woman had several cycles of in-vitro fertilisation (IVF) and although she did not become pregnant, the scientists said the prospect of restoring fertility to patients with frozen ovarian tissue and enabling them to become mothers is now more promising. "In humans this is definitely the first embryo (from an ovarian transplant,)" Dr. Kutluk Oktay, who headed the research team told.

"It creates a potentially viable option (to have children) for hundreds of thousands of cancer patients of reproductive age around the world."

The research, reported online by The Lancet medical journal, shows that women can preserve their fertility by freezing their ovarian tissue and that pregnancy may be possible even after the tissue remains frozen for a long

time.

The tissue from the woman had been frozen six years earlier.

The research is significant because cancer treatments such as radiotherapy, chemotherapy and radical surgery can cause premature menopause and infertility in hundreds of thousands of young cancer patients each year.

By removing and freezing ovarian tissue before treatment, scientists hope to enable these women to give birth to children using their own eggs. The technique has been used successfully in sheep to produce live animals.

"It (the tissue transplant) is likely to give years of function which would be sufficient to generate a baby and that is the goal," Oktay said.

Fertility centers are already freezing ovarian tissue and eggs from women before undergoing cancer treatment. But freezing can damage eggs, which are very fragile and few survive the freezing and thawing process.

Transplanting the ovarian tissue back into the patients is also difficult and there is the danger that the tissue may contain cancerous cells. But putting the transplant beneath the skin of the abdomen reduces the health risks and it can be easily removed if necessary.

Source: http://www.reuters.com