“…Therefore, in cases of AML lacking the classic t(8;21) one should be alerted to the possibility of a cryptic AML1-ETO rearrangement on detection of del(9q) and/or loss of a sex chromosome, 10,22,32 or of a cryptic CBF-MYH11 fusion in the presence of +22, 13,14,16,33,34 particularly in conjunction with suggestive morphology. However, it should be appreciated that although cases with cryptic AML1-ETO gene fusions may share the distinctive morphological features associated with the t(8;21) and those with cryptic CBF-MYH11 fusions may exhibit an M4eo phenotype, this is not invariably the case 10,11,13,14,16,23,33,35,36 suggesting that molecular screening should not be solely targeted to such patients. Furthermore, the majority of cases of AML with del(9q) or +22 have been shown not to have underlying cryptic CBF gene rearrangements.…”