British and American scientists have succeeded in growing human eggs in vitro from a very early stage “up to full maturation”. This is a “landmark” procedure that could be used to preserve fertility in girls with cancer. However, the study published in the Molecular Human Reproduction journal is kept in perspective by a certain number of comments such as “interesting results” but “there’s still a lot of work to do”, according to Professor Azim Surani at Cambridge University, who also notes that “these eggs are smaller than average”. As far as Robin Lovell-Badge is concerned, the technique “is still really very inefficient”: “nine cells out of a high, unknown number actually reached the mature egg stage”. “It will take several years to translate that into therapy,” according to Doctor Channa Jayasena from Imperial College, London.
In the past, other teams have carried out studies in mice, and have managed to produce live offspring from cultured murine eggs. Similar studies in humans have not reached the maturation stage. Professor Evelyn Telfer from Edinburgh University, who directed the last study, explains that she worked on the composition of the culture medium. She is now asking for confirmation that eggs maturing in vitro “can be fertilised” [which suggests the creation of embryos for research purposes].
 Before girls or women undergo chemotherapy, ovarian tissue samples can be harvested to prevent them from being damaged by the treatment. However, their reimplantation after chemotherapy poses the risk of reintroducing cancerous cells. The approach developed here would allow these women to culture in vitro the eggs contained in harvested ovarian tissue, with a view to performing in-vitro fertilisation.