Breast Cancer Female, Infertility, Female
Conditions
Keywords
oncofertility, Breast cancer, Fertility preservation, Folliculogenesis, Cholesterol biosynthesis
Brief summary
Advances in cancer diagnosis and treatments have improved the 5-year survival rate for patients over the last decade. Nevertheless, cancer treatments frequently alter patient's fertility, thus compromising their ability to conceive a child after remission. Consequently, it is recommended to propose fertility preservation to patients before cancer therapy. The reference technique for preserving women's fertility the vitrification of mature oocytes after hormonal stimulation. In the context of cancer, different studies have shown that ovarian response to stimulation seems to be altered compared to healthy context, with a reduced number of mature oocytes collected, and altered oocyte quality, thus reducing the number of oocytes capable of producing a viable embryo. Hence, cancer seems to exert a deleterious impact on women's fertility. Nevertheless, the mechanisms by which the cancer may impair the ovarian functions are poorly understood. This innovative project aims to study the impact of breast cancer itself (the most frequent cancer in reproductive-aged women) on ovarian functions, and more precisely on the cholesterol biosynthesis pathway. Indeed, cholesterol homeostasis is essential for oocyte maturation and fertilization. The objectives of this study are i) to evaluate the impact of breast cancer on ovarian reserve and response to hormonal stimulation according to the molecular subtypes of breast cancer and ii) to evaluate the impact of breast cancer on ovarian cholesterol homeostasis in granulosa cells and follicular fluids. This original approach will improve the understanding of the mechanisms underlying the impact of breast cancer on ovarian functions, and will have a strong clinical impact by helping to optimize fertility preservation strategies based on tumour molecular subtypes.
Detailed description
Breast cancer patients (stratified into three molecular subgroups based on tumour hormonal status: HR+, HER2+, or triple-negative (TN)) and healthy oocyte donors (OD) are included in this study. During oocyte retrieval (for fertility preservation or oocyte donation), cumulus-oocyte complexes (COCs) are collected following ovarian stimulation. COCs are treated with hyaluronidase to separate the oocytes from surrounding cumulus granulosa cells. Clinical data regarding ovarian reserve and response to stimulation are collected. Comparative analyses are conducted between breast cancer patients and oocyte donors, as well as between each molecular subgroup (TN vs. OD, HR+ vs. OD, HER2+ vs. OD). Following retrieval, granulosa cells and follicular fluids are collected. Total RNA is extracted from cumulus cells for RT-qPCR quantification of key enzymes and regulators involved in the cholesterol biosynthesis pathway. In parallel, cholesterol levels in follicular fluid are quantified using GC-MS/MS or FID-MS/MS. This extended protocol enables both clinical and molecular comparisons to assess how breast cancer subtypes may differentially impact ovarian response and follicular environment
Interventions
OTHEROvarian stimulation
Ovarian stimulation before oocytes retrieval
Sponsors
University Hospital, Clermont-Ferrand
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 38 Years
Healthy volunteers
No
Inclusion criteria
* Women above 18 years old and below 38 years old * First hormonal stimulation cycle * No dysovulation * No cancer treatments prior fertility preservation (tumour resection, chemotherapy, radiotherapy) * Women capable of giving written informed consent to participate in the research study * Affiliated to social welfare service
Exclusion criteria
* Women below 18 years old and above 38 years old * Endocrine disease * Endometriosis * Any cancer treatments prior fertility preservation (tumour resection, chemotherapy, radiotherapy) * Previous hormonal stimulation cycle of less than six months
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fertility preservation for patients with breast cancer: Altered response to ovarian stimulation and loss of cholesterol homeostasis in ovarian follicles | 65 months | After oocyte retrieval, total RNA of granulosa cells from breast cancer patients and oocyte donors, will be extracted. Following retro transcription, qPCR will be performed |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Oocyte maturity | 36 months | Ovarian response parameters, assessed by the number of mature oocytes, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Assessment of Anti-Mullerian Hormone levels | 36 months | Ovarian reserve, assessed by Anti-Müllerian Hormone (AMH) levels, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Assessment of antral follicle count | 36 months | Ovarian reserve, assessed by antral follicle count, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Total dose of FSH administered | 36 months | Ovarian response parameters, assessed by the total dose of FSH administered, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Number of harvested oocytes | 36 months | Ovarian response parameters, assessed by the numver of harvested oocytes, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Impact of breast cancer on enzymes and regulators of the cholesterol biosynthetic pathway | 36 months | Gene expression levels of enzymes (HMGCoA Réductase, SQLE, LSS, CYP51, DHCR7, DHCR24) and regulators (SREBP2, SCAP, INSIG, LXRa, LXRb) of the cholesterol biosynthesis will be assessed in cumulus cells by RT-qPCR and compared between breast cancer patients according to the molecular subtypes (TN, HR+, HER2+) and oocyte donors. |
| Oocyte atresia | 36 months | Ovarian response parameters, assessed by the number of atretic oocytes, will be compared between oocyte donors and breast cancer patients according to molecular subtypes (TN, HR+, HER2+), BRCA mutation status, tumor grade, and lymph node involvement. |
| Quantification of cholesterol and its intermediates in follicular fluids of Breast Cancer patients and Oocytes Donors | 36 months | Quantification of cholesterol and its intermediates will be assessed in follicular fluids by GC-MS/MS or GC-MS/FID and compared between breast cancer patients according to the molecular subtypes (TN, HR+, HER2+) and oocyte donors. |
Countries
France
Contacts
PRINCIPAL_INVESTIGATORFlorence Brugnon, MD, PhD, HDR
University Hospital, Clermont-Ferrand
Outcome results
None listed