In vitro analysis supported the in vivo observations, in which osteocyte-derived CM strikingly suppressed the tumorigenic behaviors of mammary tumor cells, and the overexpression of the three selected genes in osteocytes reduced the levels of tumorigenic genes such as IL1β, MMP9, Runx2, Snail, and TGFβ in breast cancer cells. This evidence concerns the gene IL1B and breast cancer.