XCT790 was able to reduce 3D spheroids formation and motility not only in H295R cells, but also in SW13 cells and, above all, in mitotane-resistant MUC-1 cells suggesting, once again, that targeting ERRα could be an effective therapy for the treatment of mitotane-resistant ACC phenotype. This evidence concerns the gene MUC1 and adrenal cortex carcinoma.