Aleix Prat, Director of Clínic Barcelona Comprehensive Cancer Center (4CB), Professor at the University of Barcelona, Co‑Founder and President of Reveal Genomics, Director of the Breast Cancer Program (IOB‑Pangaea), shared posts on LinkedIn:

“Can fertility preservation influence breast cancer biology?

This has been an important unanswered question for many young women diagnosed with breast cancer.

I’m delighted to share the publication of our study in ESMO Open, where we directly addressed this question by analyzing paired tumor biopsies obtained before and after controlled ovarian stimulation (COS) with letrozole for fertility preservation.

For the first time, we evaluated not only standard pathological markers, but also the transcriptomic landscape of breast tumors after ovarian stimulation.

The results are reassuring:

No significant changes in Ki-67, ER, PR, HER2 or tumor-infiltrating lymphocytes.
No significant alterations in gene expression or intrinsic molecular subtype.
Overall, no evidence that COS with letrozole induces short-term molecular changes in breast cancer tissue.

Beyond the scientific findings, this study is an excellent example of what can be achieved through multidisciplinary collaboration. It brought together the Assisted Reproduction Unit and our Translational Genomics laboratory within the Clínic Barcelona Comprehensive Cancer Center (4CB), combining expertise in fertility preservation, breast oncology, pathology and molecular genomics to answer a question that truly matters to patients.

This is precisely what a Comprehensive Cancer Center should do: connect disciplines to generate evidence that directly improves patient care.

Congratulations to Dr. Yasmina Barral El Gaoui, Dr. Dolors Manau MD, PhD, Fara Brasó Maristany and all the colleagues from the Assisted Reproduction Unit, Medical Oncology, Pathology, who made this work possible.

Young women with breast cancer should never have to choose between receiving the best cancer treatment and preserving the possibility of future motherhood. Evidence like this helps make that conversation more informed and more reassuring.”

Title: Molecular effects of ovarian stimulation for fertility preservation in breast cancer: a paired-biopsy analysis

Authors: Y. Barral El Gaoui, F. Brasó-Maristany, A. Borrás Capó, G. Casals, I. Agustí, G. Altinier, N. Chic Ruche, P. Galván, S. Ganau, B. González-Farre, C. Salvador, S. Peon, M. Méndez, M. Vidal, A. Prat, D. Manau Trullás