Figure 2.

Design of the study. A total of 72 patients were identified as “IKZF1-deleted” (more than 2 exons of IKZF1 were lost). Some patients have been classified by MLPA analyses as “Δ6” (n=3) and “Δ8” (n=1); these patients have been included in our study. The patients with IKZF1 Δ2-7 and Δ4-7 were directly analyzed by available PCR tests (n=16). All others (n=40) and the 16 patients from Brazil were directly subjected to LDI-PCR analyses. The obtained information was translated into the establishment of a multiplex PCR method which allows for identification of IKZF1-deleted patients by two independent PCR reaction (MP-PCR A and B). The novel method was validated in a cohort of 88 unscreened pediatric ALL patients. These analyses revealed 8 positive patients.