ATM and B-cell chronic lymphocytic leukemia: Examples of emerging subclones in CLL/SLL samples uniquely detected only by CD19S FISH include: i) two subclones including one with ATM and TP53 deletions and one with MYC rearrangement, both likely derived from a stem‐line with an ATM deletion (Table S1, Sample 128), ii) a subclone with ATM deletion from a trisomy 12 stem‐line (Table S1, Sample 45), and iii) two subclones containing heterozygous deletion of 13q14, and 13q14 deletion plus trisomy 12, derived from a stem‐line with deletion TP53 (Table S1, Sample 77).