The Expression of CD109 in B-Cell Acute Lymphoblastic Leukemia and Its Potential as a Promising Marker for Minimal Residual Disease (MRD) Detection

Background CD109 is overexpressed in various tumors, but its role in hematologic malignancies, particularly acute B lymphoblastic leukemia (B-ALL), remains unclear. Methods CD109 expression was assessed at both mRNA and protein levels in B-ALL patients using real-time quantitative PCR (RQ-PCR) and multiparameter flow cytometry (MFC). The relationship between CD109 expression and clinical and laboratory parameters was examined. The potential of CD109 as a marker for minimal residual disease (MRD) detection was evaluated. Functional studies were conducted in leukemia cell lines. Results CD109 mRNA was significantly upregulated in newly diagnosed and relapsed B-ALL patients compared to healthy controls and remission cases. MFC revealed CD109 positivity in 79.0% of B-ALL blasts, with higher rates in relapsed cases (85.7%) and CD34 + B-ALL patients. CD109 expression was minimal in mature B cells and precursors B cell. CD109 expression remained stable across disease phases including diagnosis, MRD positivity and relapse. Functional assays demonstrated that CD109-positive Nalm6 cells exhibited significantly increased proliferative and invasive abilities. Conclusion CD109 is upregulated in B-ALL and promotes leukemia cell proliferation and migration. Its consistent expression across disease stages suggests it may be a reliable marker for MRD detection, highlighting its clinical significance in leukemia management.