MOLECULAR ASSIGNMENT OF A TRANSLOCATION BREAKPOINT IN ACUTE MYELOID-LEUKEMIA WITH T(8,21)

An 8;21 translocation is a common chromosome abnormality associated with acute myeloblastic leukemia with maturation (M2 of French-American-British (FAB) classification), We have isolated chromosome 21 NotI linking clones; pulsed field gel electrophoresis analysis with one clone (LL263) detected an altered fragment of NotI-digested leukemic cell DNA carrying t(8;21). The altered fragment was shown to be produced by the 8;21 translocation. The breakpoint in chromosome 21 was located about 13 kb to 100 kb proximal to the LL263 NotI site. Because the LL263 clone has a CpG island and is a short distance from the breakpoint, the clone itself may be considered as a candidate for part of the t(8;21) associated gene.