S100A9 and breast cancer: First, it could be noticed that, in murine models of breast cancer, S100A9 antibodies have been used in conjunction with single-photon emission computed tomography (SPECT) for the in vivo detection of S100A8/A9 as a marker for the establishment of the pre-metastatic niche suggesting the interest of evaluating S100A8 and S100A9 for the stratification of patients [67,68].