Immunophenotyping with CD135 and CD117 predicts the FLT3, IL-7R and TLX3 gene mutations in childhood T-cell acute leukemia

Abstract

With the combination of immunophenotyping and molecular tests, it is still a challenge to identify the character istics of T cell acute lymphoblastic leukemia (T-ALL) associated with distinct outcomes. This study tests the pos sible correlation of cellular expression of CD135 and CD117 with somatic gene mutations in T-ALL. One hundred sixty-two samples were tested, including 143 at diagnosis, 15 from T-lymphoblastic lymphoma at relapse, and four relapse samples from sequential follow-up of T-ALL. CD135 and CD117 monoclonal antibodies were includ ed in the T-ALL panel of flow cytometry. The percentage of cells positivity and the median fluorescence intensity were correlated with gene mutational status. STIL-TAL1, TLX3, FLT3 and IL7R mutations were tested using stan dard techniques. STIL-TAL1 was found in 24.8%, TLX3 in 12%, IL7R in 10% and FLT3-ITD in 5% of cases. FLT3 and IL7R mutations were mutually exclusive, as were FLT3-ITD and STIL-TAL1. Associations of CD135high (p b 0.01), CD117intermediate/high (p = 0.02) and FLT3-ITD, CD117low with IL7Rmutated (p b 0.01) and CD135high with TLX3pos were observed. We conclude that the addition of CD135 and CD117 to the diagnosis can predict molecular aberrations in T-ALL settings, mainly segregating patients with FLT3-ITD, who would benefit from treatment with inhibitors of tyrosine.