Downregulation of TREM2 correlated with AML occurrence and inferior prognosis. (A) TREM2 profiles in peripheral blood mononuclear cells (PBMCs) from patients with AML (n = 20) and healthy individuals (n = 10; GSE33223). (B) TREM2 profiles in CD34⁺ blasts from patients with newly diagnosed AML (n = 3) and CD34⁺ cells from healthy donors (n = 3; GSE90062). (C) Overall survival in patients from the data given in GSE37642. Patient samples in the data sets of GSE37642 were from mononuclear cells (MNCs) isolated from BM aspirates from patients with AML. Log-rank analysis comparing different groups of patients (separated into tertiles) based on relative TREM2 expression (low TREM2 expression [n = 208] and high TREM2 expression [n = 209]). (D) The quantitative reverse transcription polymerase chain reaction analysis of TREM2 expression in bone marrow mononuclear cells (BMMCs) of patients with AML (n = 30) and CD34⁺ cells from healthy volunteers (n = 9). GAPDH was used as an internal reference gene. (E) Western blot analysis showing TREM2 expression in bulk BMMCs from healthy donors (n = 3) and patients with AML (n = 9) using GAPDH as an internal loading control. (F) Representative flow cytometry analysis of TREM2 expression in BMMCs from patients with AML (n = 18) and healthy individuals (n = 7). (G) Percentage of TREM2-positive cells in CD34⁺ cells from healthy donors (n = 7) and patients with AML (n = 18). (H) Mean fluorescence intensity (MFI) of TREM2 in CD34⁺ cells from healthy donors (n = 7) and patients with AML (n = 18). (I) Serum levels of IL-34 from patients with AML (n = 52) and healthy controls (n = 10). (J) Microarray data analysis of samples from patients with AML samples showing a significant positive correlation between the expressions of TREM2 and IL-34.