Monkey birth is a step forward to preserve the fertility of boys with cancer

Scientists are increasingly looking to help young boys undergoing cancer treatment to preserve their future fertility – and evidence is the first monkey born from experimental technology.

More and more people are surviving childhood cancer, but nearly one in three will remain infertile because of chemotherapy or radiation therapy that has saved their lives. When cancer is diagnosed in young adults, they can freeze sperm, eggs or embryos before treatment. But children diagnosed before puberty can not do so because they do not produce mature eggs or sperm yet.

"Fertility problems in children with cancer have been ignored" for years, said University of Pittsburgh reproductive scientist Kyle Orwig.

The Orwig team reported an important advance yesterday: first, it froze some testicular tissue in a monkey that had not yet reached puberty. Later, they used it to produce sperm that, thanks to a version for monkey from IVF, gave birth to a healthy monkey called Grady.

The technique worked pretty well so that the tests on humans could begin in the next few years, said Orwig.

"It's a huge step forward" that should give families hope, said Susan Taymans of the National Institute of Child Health and Human Development, who helped fund research published in the journal Science. "It's not like science fiction."

The University of Pittsburgh Medical Center and a handful of other hospitals are already freezing immature testicular tissue from young cancer patients, hoping to know how to use it as an adult and ready to have their own children.

The Orwig team froze the tissues of young male monkeys and then sterilized them. Once the monkeys approached puberty, the researchers thawed these tissue samples and returned them to the original animal – implanting them just under the skin.

Reinforced by hormones, small pieces of tissue have developed. Months later, the researchers removed them. Of course, inside, there was sperm that they could collect and freeze.

Colleagues at Oregon's National Primate Research Center injected some of this sperm into the eggs of female monkeys and implanted the resulting embryos. Last April, Grady was born and "she plays and behaves like any other monkey that has grown in a normal way," Orwig said.

The technique is similar to a feminine option. Girls' eggs are immature before puberty. The researchers removed and frozen strips of ovarian tissue containing egg follicles from young women prior to cancer treatment, in the hope that, once grafted, the immature eggs would resume their development. It is considered experimental even for young adults, but some births have been reported. Now, some hospitals also store ovarian tissue in girls.

– AP