Various studies have analyzed HMEC spheres grown in different media types, including standard HMEC media, conditioned media from breast cancer cell lines SUM149PT and SUM1315MO2, OPG-depleted conditioned media, and HMEC media supplemented with recombinant human OPG at concentrations of 500 pg/mL and 1100 pg/mL. This evidence concerns the gene TNFRSF11B and breast cancer.