STAT3 and neoplasm: Moreover, flow cytometry analysis of TRAMP/MICB spontaneous prostate tumor model implies that the number of MDSCs in the spleen and tumor infiltration area significantly correlates with serum levels of soluble MHCI chain-related molecule (SMIC), the ligand of NKG2D, which activate STAT3 and induce MDSCs amplification as well as M2 polarization [93].