TCF3-PBX1⁺ GIPFEL results for samples N15 and N141. (A) Result of the first RT-PCR analysis of N15. The amplification of the 5 PBX1 primer bundles (1 through 5) was compared with the amplification of the internal PBX1 wild-type control (Ctrl). Primer bundle 3 leads to a detectable amplification. (B) Amplification plot of the second RT-PCR analysis of N15. The forward primers of bundle 3 were de-multiplexed, and primer PBX1-M20f was identified as the primer responsible for the amplification. (C) Agarose gel analysis of N15 after a PCR assay with PBX1-M20f and the reverse primer TCF3-M1r-n. The PCR data show the expected product of 158 bp. (D) Sanger sequencing result of UCB sample N15. The expected sequences flanking the MfeI ligation joint (gray) were identified, indicating the fusion of PBX1 segment M20 to TCF3 segment M1. (E) Sanger sequencing result of the chromosomal breakpoint of sample N15. Bases on a gray background indicate nontemplate bases. (F) Same as (E), but for sample N141. ΔCq, normalized quantification cycle, with the PBX1 wild-type control set as 1.