With
the combination of immunophenotyping and molecular tests, it is still a challenge to identify
the characteristics of T cell acute lymphoblastic
leukemia (T-ALL) associated with distinct outcomes. This study tests
the possible 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 included 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 standard 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 < 0.01), CD117intermediate/high (p = 0.02) and FLT3-ITD, CD117low with IL7Rmutated (p < 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.