Cryopreservation of testicular tissue in young cancer patients

Cryopreservation of testicular tissue might benefit prepubertal boys who mu st undergo chemotherapy or radiotherapy. Cryopreservation of testicular tis sue and testicular cells for intracytoplasmic sperm injection (ICSI) is fea sible and widely applied. Testicular tissue from prepubertal boys can also be frozen, by applying techniques used with other tissues and with testicul ar tissue from adult men before ICSI. Good results have been obtained when propanediol is used as a cryoprotectant, but glycerol has also been used wh en freezing testicular tissue, Spermatogonia might also be isolated and cry opreserved as a cell suspension, though practical experience in humans is l acking. Transplantation of the frozen-thawed cells back to the testes after cancer treatment might result in restoration of spermatogenesis. Live offs pring have been born to mice after transplantation of fresh, but not cryopr eserved, testicular cells. Transplantation is technically feasible also in larger species, but to date no offspring have been born. Spermatogenesis in vitro would be an excellent option for boys with haematological malignanci es who carry a risk of relapse after transplantation; however, at present t he method is feasible only for the late stages of spermatogenesis.