CD33 and neoplasm: Analyses of the tumor tissue revealed an overall low immune cell infiltration (range: 0–2.5%; Figure 6I) in MDA-MB-453 transplanted HTM with a majority of T cells (MDA-MB-453CX3CL1 HTM: 66.4 ± 7.6 SEM; MDA-MB-453empty HTM: 64.2 ± 7.2; data not shown) followed by CD33+ myeloid cells (MDA-MB-453CX3CL1 HTM: 18.1 ± 4.7 SEM; MDA-MB-453empty HTM: 20.4 ± 5.8 SEM) and B cells (MDA-MB-453CX3CL1 HTM: 7.9 ± 4.7 SEM; MDA-MB-453empty HTM: 8.5 ± 3.2, n = 15 for all groups).