Breast cancer: an update on treatment-related infertility.

Breast cancer (BC) is the most common malignancy in women with a significant increasing incidence during the reproductive life. However, based on the newest anti-cancer molecular targeting drugs, successful treatments lead to the disease healing particularly in young patients, thus refreshing their motherhood programs. However, as effect of the BC treatment, a premature depletion of the ovarian follicle reserve occurs in more than one-third of patients resulting in permanent infertility. To prevent the cancer treatment-related infertility (CTRI), several options are today utilized. Besides the ovary suppression by gonadotropin-releasing hormone agonist (GnRHa), other procedures include either oocytes or embryos cryopreservation as well as ovarian cortex cryopreservation that are currently adopted before anti-cancer therapies. These modern techniques appear variably successful in terms of pregnancy rate though their safety concerning the hormonal stimulation to promote the folliculogenesis is still debated in relation to the potential oncogenic risk in patients bearing hormone-sensitive tumors as BC, while the ovarian cortex re-implantation often results in a low number of regenerated follicles including oocytes of unknown quality. Recent studies on ovarian stem cells (OSCs) suggest their use for future application in CTRI. In fact, OSCs from ovarian cortex have been shown to differentiate in vitro into oocyte-like cells (OLCs) and express molecular markers of mature oocytes. Once the OSC technology will be optimized and translated to clinical use, oocytes derived from these cells will be molecularly assessed before fertilization to assure their best embryo quality resulting in a safe procedure to treat CTRI in patients as young women with BC.