t(15;17)(q22;q21 or12)
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.