Sequences flanking the breakpoints in four patients withETV6-AML1 rearrangements. RUPN refers to unique patient number. Sequences from the ETV6 germline (GL ETV6), AML1germline (GL AML1), and the two derivatives, derivative 12 (DER 12) and derivative 21 (DER 21), are shown. Nontemplated nucleotides are shown in lower case. Nucleotide sequences with at least a 5/7 match to the consensus V(D)J heptamer recognition sequence (CAC A/T GTG) are shown with asterisks.