A prenatal origin of translocations associated with pediatric leukemia has been demonstrated for MLL-AF41 in infant leukemia, TEL-AML12, 3 in common acute lymphocytic leukemia (cALL), and AML1-ETO4 in acute myeloid leukemia (AML). We investigated whether AML-associated translocations PML-RARA and CBFB-MYHII could arise before birth. PML-RARA arises from the t (15; 17) translocation, 5 characteristic of acute promyelocytic leukemia (APL) 6 (AML FAB subtype M3), while CBFB-MYHII arises from inv (16)(p13q22) 7 and t (16; 16). 8

Diagnostic samples from 2 t (15; 17) and 2 inv (16) cases were obtained with informed consent and ethics committee approval from patients enrolled in the Northern California Childhood Leukemia Study (NCCLS) and from the Children’s Oncology Group AML cell bank. Corresponding Guthrie cards (neonatal blood spots) for patients were obtained from a central repository maintained by the Genetic Diseases Branch of the California Department of Health Sciences. We obtained genomic breakpoints from patients by multiplex long-distance polymerase chain reaction (PCR) using eLONGase DNA polymerase (Invitrogen Life Technologies, Carlsbad, CA), according to manufacturers’ instructions, and sequenced the translocation junctions. For each PML-RARA case, 10 multiplex reactions were set up, containing 2 PML primers from bcr3 (intron 3; 1447 bp) or bcr1 (intron 6; 1056 bp), in combination with 1 of 5 RARA primers. For each CBFB-MYHII sample, 6 individual PCR reactions were set up using 1 of 6 CBFB primers (targeted to intron 5; 16 359 bp) in combination with the single MYHII primer (targeted to intron 11; 370 bp). Primer sequences are available on request.