. 2019 Oct 22;12:105. doi: 10.1186/s13045-019-0797-3

Table 2.

MDSCs in multiple myeloma

Disease cases (n)	MDSC subgroups/phenotype definition	Clinical finding	Mechanism/intervention	Year/reference
MM, n = 15	G-MDSCs CD11b + CD14-CD33 + CD15+	PB and BM Higher MDSCs vs. healthy donor	S100A9 knockout reduced MDSC accumulation in BM after injection of MM cells	2013 [41]
MM, n = 93	M-MDSCs CD14⁺HLA-DR^low/−	Higher MDSCs diagnosis vs. healthy donor Higher MDSCs in relapsed MM Decreased M-MDSCs after treatment indicated good response	MM cells were able to induce the accumulation of M-MDSCs in vitro, MDSCs induced Treg	2014 [44]
MM, n = 17	G-MDSCs CD11b + CD14-CD33 + CD15 + HLA-DR^low	Higher MDSCs vs. healthy donor associated with the activity of disease in MM	MM cells induced the development of MDSCs from healthy donor peripheral blood mononuclear cells	2013 [45]
MM, n = 6	G-MDSCs CD11b + CD14-CD33 + CD15 + HLA-DR^low	Higher MDSCs in progressive MM vs. healthy donor	MM MDSCs induced the generation of Treg G-CSF increased G-MDSCs	2014 [46]
MM, n = 45	G-MDSCs CD11b + CD14-CD33 + CD15 + HLA-DR^low	MGUS and MM were able to generate the same amount of MDSC, only MM-MSC-educated G-MDSC exhibited suppressive ability	MM G-MDSCs upregulated immune-suppressive factors as ARG1 and TNFalpha, expressed higher levels of PROK2, showed ability to digest bone matrix.	2016 [47]
MM, n = 72	G-MDSCs HLA-^DR−/low/CD33⁺/ CD11b⁺/CD15⁺/CD14−	Higher frequencies of G-MDSCs in both the PB and BM from MM patients, significantly correlated with disease burden by ISS stage.	G-MDSCs enhanced the side population, sphere formation, and expression of cancer stem cell core genes in MM cells. Silencing of piRNA-823 in MM cells reduced the stemness of multiple myeloma stem cells maintained by G-MDSCs	2019 [48]