CD34 EXPRESSION IS ASSOCIATED WITH MAJOR ADVERSE PROGNOSTIC FACTORS IN ADULT ACUTE LYMPHOBLASTIC-LEUKEMIA

Seventy-five adult patients with newly diagnosed acute lymphoblastic l eukemia (ALL) were analyzed for CD34 expression on leukemic cells. CD3 4 was significantly associated with B-cell lineage ALL (p = 0.0002). I n B-lineage ALL, CD34 positivity was significantly associated with exp ressions of CD9 (p = 0.001), CD19 (p = 0.00001) and CD22 (p = 0.002). CD34 was more expressed in B-ALLs with higher WBC cell count (p = 0.04 ), and higher percentage of peripheral blood leukemic cells (p = 0.005 ), total or partial monosomy of chromosome 7 (p = 0.0001) or Ph+ chrom osome (p = 0.01); and less expressed in cases with hyperdiploidy (grea ter than or equal to 50 chromosomes) (p = 0.03). CD34 was more express ed in poor risk B-ALLs patients, defined according to Hoelzer criteria (p = 0.01). In T-lineage ALL, CD34 positivity was inversely correlate d with the expression of CD10 (p = 0.05). After intensive induction th erapy, 58 of 73 evaluable patients (79%) achieved a complete remission (CR). CD34 positivity was correlated with the persistence of blast ce lls in day 15 bone marrow aspirates (p = 0.001) and after one course o f induction chemotherapy (p = 0.01), With a median follow-up of 11 mon ths, no statistical differences were seen in leukemia-free survival an d overall survival between CD34 positive and negative cases, even when stratifying by immunophenotype. We conclude that CD34 expression is a ssociated with features of poor prognosis in adult ALL. Its study migh t therefore become useful in the design of future prognostic models.