Survival rates for patients with cancer have continuously increased over the past decade as a result of more advanced cancer treatment. As a consequence, adverse side effects of cancer therapy becomes an important health issue for these cancer survivors. Male sterility is a relative common side effect of cancer treatment. This adverse fertility effect is caused by gonadotoxic effects as the cancer treatments not only effectively kill cancer cells but also destroy the progenitors of sperm. Spermatogenesis is the process of sperm production starting from spermatogonial stem cells that are extremely sensitive to treatments with alkylating agents or irradiation. Damage to these stem cells results in temporary or permanent sterility depending on the doses. For this reason, adult men diagnosed with cancer are offered cryopreservation of semen before starting cancer treatment. However, for pre-pubertal and young boys, this is not an option as sperm is not yet produced in these boys. As spermatogonial stem cells are already present in the testis, these cells are a source for fertility preservation. A potential future clinical application to preserve fertility in these boys with cancer is to cryopreserve a small testis biopsy prior to cancer treatment for later isolation and propagation of spermatogonial stem cells from this biopsy and transplantation of these cells back after cure of cancer. Studies in animal models have provided evidence that this method indeed restores fertility. It is shown that spermatogonial stem cells can be transplanted to the testis, where they migrate to their niche and colonize the testis, giving full spermatogenesis of which sperm was able of fertilizing eggs and producing offspring. Using this transplantation as readout, spermatogonial stem cell characteristics could be studied in more detail, resulting in the establishment of a long term in vitro propagation system for mouse spermatogonial stem cells that upon transplantation could produce sperm to generate offspring. This presentation will give an overview on the state of art of the translation of these techniques to the human situation to establish a clinical application for fertility preservation in young boys suffering from cancer.
20 - 23 May 2017
European Society of Endocrinology