Cryopreservation of ovarian tissue is offered to young girls and women aged under 35 who have to undergo sterilizing gonadotoxic treatment, with the aim of preserving their fertility. The main part of the ovary is preserved, as primordial and primary follicles are resistant to freezing / thawing protocols. In the absence of other techniques (in vivo maturation, injecting isolated ovarian follicles, etc.) autografting this cryopreserved tissue is currently the only technique allowing fertility to be restored. Autograft is possible only if the indication for ovary cryopreservation is a non-neoplastic pathology or a malignant pathology with a low risk of ovarian metastasis. In other cases of neoplastic pathologies, particularly in cases of acute leukemia, tissue cannot as yet be re-used due to the lack of any codified technique for evaluating residual disease (MRD). The team has for two years been developing and validating a technique to look for residual disease in fragments of ovarian cortex in cases of acute leukemia. This technique is based on an original protocol for dissociating ovarian tissue to obtain a population of isolated ovarian cells that may be analyzed by multicolor flow cytometry. The specificity and sensitivity of the technique have been demonstrated in an experimental model. This model consists in using 8 color flow cytometry to look for characterizable leukemia cells added in different dilutions to a population of isolated ovarian cells taken from model ovarian cortex and up to a dilution of 10-5. When the molecular markers were present on diagnosis, they were found by Real-Time Quantitative Polymerase Chain Reaction (RQ-PCR) with the same dilutions. The model tissue came from laparoscopic ovarian drilling in patients with polycystic ovary syndrome. The main objective of this project is to validate techniques that have been previously codified with different populations of leukemia cells that may be characterized. The investigators then aim to adapt and validate this technique to look for MRD using 8 color flow cytometry on cryopreserved fragments of ovarian cortex from leukemia patients that are at risk of metastasis. Secondary objectives will be to implement procedures for oncological qualification of grafts in cases of malignant pathology and to consider the recommendations for using this cryopreserved ovarian tissue through the autograft technique for these indications.

Inclusion Criteria:

• Patients who have cryopreserved their ovarian tissue
• Patients with premature ovarian insufficiency
• Patient aged from 18 to 43 years for the restoration of ovarian function
• No objection from the patient

Exclusion Criteria:

• Patients Under 18 years
• Patients older than 43 years
• Patients refusing to be included
• Patients (adults) Under guardianship, curators ans safeguard justice

Ovarian cortex residues, coming from the preparation of ovarian cortex fragments, will be used as study material for research of the Minimal Residual Disease (MRD). Tissues will be obtained in patients candidates for cryopreservation of ovarian tissue before their gonadotoxic treatment against acute leukemia.