Fertility preservation in male childhood cancer.

The recovery and survival rate of children diagnosed for cancer has improved thanks to effective radio- and chemotherapy. One subgroup of children, especially those who need aggressive treatment including chemotherapy and bone marrow transplantation are at risk of life-long sterility.

Because spermatogenesis only starts around puberty, prepubertal boys cannot benefit from the possibility to cryopreserve semen before the onset of the treatment. Because the progenitor cells for spermatogenesis, the spermatogonial stem cells (SSCs) are present in the testis already at the time of birth, cryopreservation of SSCs or testicular tissue followed by spermatogonial stem cell transplantation may offer new strategies for preservation of fertility in young pre-pubertal boys.

We developed a cryopreservation protocol for mouse SSCs and testicular tissue and we have proven the efficiency and safety of SSC transplantation in a mouse model. These results have been published in peer-reviewed journals and have been presented on (inter)national meetings.

Since a couple of years, the interest in fertility preservation has grown. Therefore, a testicular tissue bank has been set up in the UZ Brussel. However, using existing cryopreservation protocols, too many SSCs do not survive and/or loose their functionality after freezing and thawing. Optimized cryopreservation strategies are absolutely necessary.

As it is of high importance that the functionality of SSCs is maintained during the freezing and thawing procedure, the present project aims at improving cryoprotocols with a focus on the functional capacities of SSCs.