Of note, del(5q) occurs as a secondary abnormality in at least two subtypes of AML with cryptic abnormalities: t(5;11)(q35;p15)/NUP98-NSD1 and the rare t(7;21)(p22;q22)/RUNX1-USP42, thus emphasizing the need for a complete cytogenetic and molecular screening of such cases [29,128,129]. This evidence concerns the gene RUNX1 and acute myeloid leukemia.