47XY 8+ t(9;22)

t(9;22) is associated with Chronic Myeloid Leukaemia (CML). It fuses ABL1 from chromosome 9 with BCR on Chromosome 22. Disease progression will occur to accelerated (CML-AP) or blast crisis (CML-BP) with additional genetics and molecular events. Approximately 30% of patients with CML-AP and 70–80% of patients with CML-BP have additional cytogenetic abnormalities (ACA).

Trisomy 8 (+8) and an extra copy of philadelphia chromosome (Ph) are the most common. Some ACAs are associated with disease progression and treatment resistance, whereas others may simply reflect genetic instability. According to World Health Organization (WHO) criteria, any new clonal chromosomal abnormality in t(9;22) positive cells occurring during therapy is considered criteria for AP.

Studies have shown that trisomy 8 present at initial diagnosis is not been shown to have prognostic impact however if it develops during therapy, it is associated with a poorer prognosis. This maybe confounded by the presence of additional blasts also seen with the emergence of trisomy 8. Further analysis with exclusion of patients with additional confounding factors suggested that the poorer survival was not statistically significant.