Egg freezing and gene expression

Dear Professor Winston,

I was recently reading an article and it quoted you saying saying something about freezing of eggs alters a gene that may increase the risk of cancer. I had my baby using vitrification -should I worry? Thank you, D.

Dear D,

I did not say this. But this is a highly complex area and it would foolish to pretend that the effects of these procedures as children grow into adults and old age is really understood. There may be few or even no long-term effects at all but there are a number of good reasons why we need to be aware there may be some risks. It will take many years before we can judge their safety which is why I advocate caution about any form of advanced reproductive technology which is not really essential – especially when it involves our children or unborn babies who cannot, of course, give informed consent. Of course, supporters of these technologies frequently say that if we had taken this view 40 years ago there would now be no IVF babies. And IVF is, of course, an undoubted, wonderful boon. But the more we meddle with an embryo – or indeed a human egg – the more we get into unknown territory and there are enough unpredicted events occasionally reported with advanced IVF to be aware that it is only responsible to be careful.

With regard to the risks of embryo (not egg) freezing you may care to read Maria Tachataki’s paper, “Quantitative RT-PCR reveals tuberous sclerosis gene, TSC2, mRNA degradation following cryopreservation in the human preimplantation embryo” from work done in my lab many years ago*. This research was supported by the Genesis Research Trust and I think this area needs a lot more study but sadly the commercial interests of clinics have rather taken over the field in recent years.

*Tachataki M, Winston RM, Taylor DM. Molecular Human Reproduction, 10:593-601 (2003).

Best wishes
Robert Winston