Germ cell transplantation as a toot for fertility preservation of oncological patients

Spermatogonia are the diploid cells in the testis, representing a small sel f-sustaining pool of male germ line stem cells as well as a larger pool of differentiating germ cells which enter the process of spermatogenesis. Afte r going through prophase of meiosis as spermatocytes these cells finally le ave the testis as sperm. Spermatogonia share many characteristics with othe r stem cells but also carry some specific physiological features. Many deta ils about the kinetics of spermatogonial divisions, about the hormonal regu lation of their expansion and differentiation and about their clinically re levant involvement as a cause for male infertility are poorly understood. H owever, the loss of spermatogonia following chemo- or radiotherapy leading to temporary or permanent infertility of the patient is a well known arid u nwanted site effect of many oncological therapies. Isolation and extracorpo ral storage of spermatogonia prior to the treatment and transplantation int o the testis after recovery from the disease presents a promising future to ol for fertility preservation in male patients undergoing oncological thera py.