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
