In cells grown in 3D, progestins regulate a group of breast cancer-associated genes that are also regulated in 2D including CDH10, PGR, CHEK2, LSP1, TERT, SDPR, but also a new set of 3D-exclusive genes, associated to the ECM including members of the integrin family, Laminins, and AKT3. This evidence concerns the gene CHEK2 and breast cancer.