Ovarian tissue banking and fertility preservation in cancer patients: histological and immunohistochemical evaluation

Abstract

Objective A combination of chemotherapy and radiotherapy in young females with cancer has greatly enhanced the life expectancy of these patients, even if these treatments have a highly deleterious effect on the ovary and cause a severe depletion of the follicular store. Cryopreservation of ovarian tissue before chemotherapy and/or radiotherapy, followed by autograft after remission or in in vitro maturation, could restore gonadal function and fertility. The aim of this study is to verify the efficiency of the ovarian tissue cryopreservation procedure by histological and immunohistochemical analyses. Methods Ovarian tissue was obtained by laparoscopy from 22 patients affected with different malignant diseases. Tissue specimens were frozen using a combination of PROH (1,2-propanediol) and sucrose as cryoprotectants, and the cryopreservation protocol used consisted of a slow freezing–rapid thawing program. Both fresh and frozen/thawed tissues were embedded in paraffin blocks for histological and immunohistochemical analyses. Results Good stromal and follicular morphology was found in fresh and frozen/thawed tissue. No significant differences were found in follicular density, distribution, and diameters in fresh and frozen/thawed tissue. Follicle immunohistochemical analysis showed a high percentage of negative staining for both estrogen receptor (ER) (100% both in fresh and frozen/thawed specimens) and progesterone receptor (PR) (97% versus 91%, respectively). Regarding the Ki67 protein, positive staining was found in both the granulosa cells and/or the oocytes (36% in fresh and 56% in frozen/thawed). For the Bcl2 protein, positive staining was observed in the follicle granulosa cells but not in the oocytes in 74% of the fresh and in 79% of the frozen/thawed specimens. For the stromal cells, ER showed a negative staining distribution in 97% of the fresh and 100% of the frozen/thawed specimens. The stroma staining distribution was diffuse/focal in fresh versus frozen/thawed specimens (50% versus 74% respectively) for PR, patch/focal (70% versus 80%, respectively) for Ki67 protein, and diffuse (55% versus 54%, respectively) for Bcl2. Conclusions These results suggest that human ovarian tissue morphology, antigenicity, cellular proliferation, and anti-apoptotic index were well preserved by cryopreservation in PROH and sucrose.