Comparative transcription of the PAX5 target genes CD19 and BLK by RQ-PCR in PAX5-ELN–positive and –negative patients with B-ALL. (A) CD19 mRNA levels: CD19 transcription in Patient 1 (P1) and Patient 2 (P2) is lower compared with the other patients with B-ALL (C1, C2, C3, C4, C5, and C6). (B) BLK mRNA levels: P1 and P2 display lower levels of BLK transcripts than the other patients with B-ALL. (Results are mean ± SD; Student t test: *P < .05, **P < .01 compared with Patient 1).