Endometrial cancer is the most common gynecologic malignancy in the United States, and the standard-of-care for its treatment is total hysterectomy with bilateral salpingo-oophorectomy (TH-BSO). Although the majority of patients are typically diagnosed after menopause, up to 6.5% of cases are seen in reproductive-age women at 45 years old or younger who may wish to preserve their fertility. Moreover, the share of young women is expected to grow with the increasing incidence of obesity, metabolic syndrome, and nulliparity due to delayed childbirth, all of which are significant risk factors for endometrial cancer.

The field of reproductive medicine is evolving rapidly. We are living in an era in which what was seemingly impossible a decade ago is being made possible, and century-old dogmas are being challenged. Thanks to new cryopreservation technologies, infertility and premature ovarian failure, especially when induced by medical treatments, are no longer unavoidable consequences. Whereas success with oocyte cryopreservation is gradually approaching acceptable levels for use in patients who face the risk of ovarian failure due to medical treatments or to create “egg banks” for oocyte donation, ovarian tissue cryopreservation and transplantation promise to be a way to reverse menopause and restore fertility. Yet, the recently proposed possibility of the presence of germ stem cells in human bone marrow is even more intriguing. Whereas bone marrow and peripheral blood transplants result in repopulation of chemotherapy-treated ovaries with primordial follicles in rodents, germ stem cell markers are already shown in human bone marrow and peripheral blood. According to this theory, the ovaries provide signals to the germ stem cells residing in the bone marrow and recruit new follicles via the bloodstream “on demand.” Although shocking and contrary to the preexisting dogma that the ovarian reserve is predetermined before birth, this hypothesis is not without supporting evidence in humans and nonhuman primates, as illustrated by the following case study.