Is transplantation of a few leukemic cells inside an artificial ovary able to induce leukemia in an experimental model?

PURPOSE: To evaluate the tumor-inducing ability of a few leukemic cells xenotransplanted inside an artificial ovary. METHODS: Ten and 100 BV-173 leukemic cells were embedded in a fibrin matrix along with 50,000 human ovarian stromal cells, and grafted to the peritoneal bursa of 5 and 5 SCID mice respectively. Four mice grafted with 3x10(6) leukemic cells in fibrin served as positive controls. At 20 weeks post-transplantation, the grafts, liver, spleen, blood and bone marrow were analyzed for the presence of leukemia by anti-CD79α IHC, flow cytometry (FC) and PCR. RESULTS: All mice grafted with 3x10(6) cells developed peritoneal masses 4 weeks after xenotransplantation, and systemic disease was confirmed by IHC, PCR and FC. Among mice grafted with 10 or 100 leukemic cells, none showed any sign of leukemia after 20 weeks, and IHC, FC and PCR on the different recovered tissues all proved negative. CONCLUSION: This study investigates the tumor-inducing potential of a few leukemic cells grafted inside an artificial ovary. Transplantation of 100 leukemic cells appears to be insufficient to induce leukemia after 20 weeks. These results in an immunodeficient xenografting model are quite reassuring. However, for clinical application, follicle suspensions must be purged of leukemic cells before grafting, as even the slightest risk should be avoided.

Evaluation of a human ovarian follicle isolation technique to obtain disease-free follicle suspensions before safely grafting to cancer patients.

OBJECTIVE: To evaluate the safety of our follicle isolation procedure in a model of ovarian tissue artificially contaminated with cancer cells, then to improve the procedure to effectively eliminate malignant cells from follicle suspensions without altering viability. DESIGN: Prospective experimental study. SETTING: Gynecology research unit in a university hospital. PATIENT(S): Ten women undergoing laparoscopy for benign gynecologic disease. INTERVENTION(S): Follicle isolation from ovarian tissue artificially contaminated with marked fluorescent leukemic cells, either by the usual pickup technique without further treatment (group 1) or by washing three times after pickup (group 2). MAIN OUTCOME MEASURE(S): Evidence of leukemic cells in follicle suspensions using fluorescence microscopy and quantitative real-time polymerase chain reaction, and analysis of follicle viability. RESULT(S): In group 1, 196 leukemic cells were detected by fluorescence microscopy out of 499 follicles retrieved, while just one leukemic cell was found among 772 follicles after three washes. The BCR-ABL fusion transcript was detected when at least 19 cells were present in follicle suspensions; four samples were positive in group 1, and all were negative in group 2. Follicle viability was similar in both groups (95.6% vs. 96.4%). CONCLUSION(S): Cancer cells could inadvertently be picked up with isolated follicles in case of malignant contamination of ovarian tissue. A simple purging procedure consisting of three washes proved effective for eliminating leukemic cells while maintaining good follicle viability.