Cryptic insertion of PML-RARA into the 3p25 locus in an acute promyelocytic leukemia with t(3;17)(p25;q21)

We studied a case of a 72-year-old man with acute promyelocytic leukemia and a t(3;17)(p25;q21). Fluorescence in situ hybridization failed to show rearrangement of the PML (promyelocytic leukemia protein) locus but did demonstrate relocalization of the retinoic acid receptor alpha (RARA) to chromosome 3. We performed a modified panhandle polymerase chain reaction analysis to investigate the unknown 5′ partner. Our analysis indicates that the fusion partner is PML. This karyotype therefore results in a cryptic PML-RARA fusion inserted into the 3p25 locus. Our case highlights the need for molecular analysis of seemingly novel karyotypic abnormalities.