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% B-ALL patients, 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 promising marker for MRD detection, highlighting its clinical significance in leukemia management.