Triggered by this finding we performed a similar PCR-based BTG1 deletion screening for the three most common deletions (III, V, and VIII) in 89 deletion negative BCP-ALL cases as scored by MLPA or SNP array and were able to confirm the presence BTG1 deletions in minor subclones in 16 cases (18%), which is substantially more frequent than the occurrence of this abnormality in the predominant leukemic clone (Figure 2B). Here, BTG1 is linked to acute lymphoblastic leukemia.