Establishment of an ex Vivo Tumor Collection of Triple-negative Breast Cancers in Order to Validate the Interest of Innovative Therapies and the Search for Predictive Biomarkers of Response to Treatment

Initially described in 2009 on LGR5 positive stem cells from intestine, organoids correspond to a 3D cell culture that preserves the organization and part of the initial function of the organ from which the cells were derived. They use the proliferation and differentiation properties of stem cells cultured in a three-dimensional matrix. These principles have been adapted to many human organs, including the breast. These culture conditions have thus allowed the establishment of cancer organoid lines that have the advantages of rapid amplification, a high rate of establishment success and unlimited proliferation potential. They are transfectable and cryopreservable. They are very close morphologically and genetically to the tumor from which they derive. Very recently, the in vivo response of orthotopic xenograft models of breast cancer organoids has been correlated to the in vitro response of these same organoids. In addition, the in vitro response of various of these models to PARP inhibitors was linked to the presence of the BRCA1/2 mutant signature, highlighting the potential of these models to predict patient response to these treatments. Furthermore, one study demonstrated the value of using organoids derived from metastatic gastrointestinal tumors to predict patient response to cancer treatments (100% sensitivity, 93% specificity, 88% positive predictive value, and 100% negative predictive value.