Inversions of chromosome 16 and rearrangements involving band 16q22 are almost exclusively observed in acute nonlymphocytic leukemia, specifically acute myelomonocytic leukemia (AMMoL:FAB-M4eo). This chromosome abnormality is associated with increased numbers of immature eosinophils in the bone marrow and peripheral blood. Eosinophils may show some nuclear hypo-segmentation and positive PAS/PE staining. These patients have been reported to frequently develop CNS leukemia. The inversion of chromosome 16 or a band 16q22 abnormality is reported to be suggestive of a relatively good patient prognosis.
This translocation is a remarkably specific marker for acute promyelocytic leukemia (ANLL-M3). This strong association is further exemplified by the fact that occasionally this translocation develops as a secondary aberration during CML blast transformation, with patients exhibiting disease characteristics indistinguishable from APL. Apart from these exceptional CML blast crisis patients, t(15;17) has not been detected in any malignancies other than ANLL-M3. t(15;17) APL patients usually exhibit disseminated intravascular coagulation (DIC) and hyper- or micro-granulated promyelocytes.