To verify this hypothesis we performed PCR using cDNA from NALM6 cell line (bearing ERGdel) and primary ALL samples with primers enabling simultaneous amplification of complete coding sequence of ERG2 and ERG3 (expressed from the wild type allele) and of potential aberrant transcripts (expressed from the allele affected by deletion) (Fig 1A). Here, ERG is linked to acute lymphoblastic leukemia.