CD9 expression indicates a poor outcome in acute lymphoblastic leukemia

OBJECTIVE: We undertook a single-center retrospective study to determine the relationship between CD9 and acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: In total, 112 newly diagnosed patients in our center were enrolled in the study. Their clinical information was collected and the patients werefollowed over the course of the study. Flow cytometry was used to detect the expression of CD9. RESULTS: CD9 expression was more common in B cell acute lymphoblastic leukemia (B-ALL) and patients >40 years old. CD9-positive patients exhibited a higher BCR-ABL fusion gene positive rate and higher neutrophil counts than CD9 negative patients (P = 0.004 and P = 0.004, respectively). Response to induction chemotherapy was not dependent on CD9 expression. CD9-positive patients had a lower 2-year overall survival rate than CD9-negative patients. CONCLUSION: CD9 expression predicts some clinical characteristics and indicates an unfavorable prognosis in ALL patients.