Acute Myeloid Leukemia with the t(8;21) Translocation: Clinical Consequences and Biological Implications
Figure 2
Cytogenetic analysis of AML blasts by G-banding and FISH. (a) The derivative chromosomes from a simple reciprocal translocation between 8q22 and 21q22 are detectable by G-banding (upper panel) and the translocation can be verified using FISH probes (lower panel) against ETO and AML1. With this particular probe (Vysis LSI ETV6(TEL)/RUNX1(AML1) ES Dual Color) fusion signals will appear both on derivative 8 and derivative 22. (b) In rare cases, AML1-ETO fusion occurs as a result of insertion. Small insertions can only be detected using FISH probes. In this case, the translocation t(7;8)(q11;q22) between chromosome 7 and 8 and the 9q deletion del(9)(q12q22) were detected. As deletion 9q is rare in AML and can coexist with AML1-ETO fusion, FISH analysis was, therefore, performed. Only one fusion signal on derivative 22 was detected, indicating an ins(21;8)(q22;q22q22) insertion. (c) AML1 can also be involved in translocations with other partners mimicking complex t(8;21). In this case, there is a translocation between 9q22 and 21q22. FISH analysis using in-house split-signal probes against AML1 verified the involvement of these genes, whereas the gene on derivative 9 is unknown.
