- Chromosomal abnormalities are identified in around 50% of all adult patients with AML. Although some 40-50% of AML patients have no chromosomes abnormalities, they do have other gene mutations such as the FMS Like Tyrosine Kinase 3 (FLT3) gene and the nucleophosmin 1 (NPM1) gene.
- AML genetic abnormalities, and the prognosis are shown in Table 2.
Table 2 Genetic abnormalities in AML and prognosis
| GENETIC ABNORMALITIES IN AML | PROGNOSIS |
| Chromosome abnormalities | |
| Translocations | |
| t(1;22) | Good |
| t(3;3) or inv (3) | Poor |
| t(6;9) | Poor |
| t(8;21) | Good |
| t(9;11)7 | Intermediate |
| t(9;22) | Poor |
| t(15;17) in APL | Good |
| t(16;16) or inv (16) | Good |
| Deletion/abnormalities of chromosome 5 or chromosome 7 | Poor |
| Complex chromosome abnormalities in 3 or more chromosomes | Poor |
| Gene abnormalities | |
| ASXL1 (Additional sex combs-like 1) gene mutation | Poor |
| FLT3-ITD (FMS‑Like Tyrosine Kinase-3 – internal tandem duplication gene mutation | Poor |
| NPM1 (nucleophosmin 1) gene mutation with/without FLT3-ITD gene mutation | Good |
| Non-mutated NPM1 with/without FLT3-ITD gene mutation | Intermediate |
| RUNX1 (RUNX Family Transcription Factor 1) gene mutation | Poor |
| RUNX1-RUNX1T1 fusion gene | Good |
| TP-53 (tumour suppressor 53) gene mutation | Poor |
Inv (3) is an inversion of a section of chromosome 3. This may be inherited or a random mutation. Chromosome inversion is where a chromosome has been broken at two separate points, rotated by 180 degrees, and re-joined within the chromosome.
- In chromosome abnormalities, the “t” stands for translocation. The numbers in brackets after the “t” are the numbers of the chromosomes involved in the translocation.
- With a translocation, one part of a chromosome is transferred to another part of the same or a different chromosome. This results in a rearrangement of the genes within the newly-formed chromosome.
Genetic syndromes
- Patients with syndromes due to genetic mutations are at increased risk of AML. These include:
- Neurofibromatosis type 1 (condition where generally benign tumours grow along the nerves, causing a number of symptoms)
- Down’s syndrome (extra copy of chromosome 21)
- Trisomy 8 (extra copy of chromosome 8)
