Acute leukaemia of ambiguous lineage (
ALAL) is a rare complex entity with heterogeneous clinical, immunophenotypic, cytogenetic and molecular genetic features and adverse outcome. According to World Health Organization 2008 classification,
ALAL encompasses those leukaemias that show no clear evidence of differentiation along a single lineage. The rarity of
ALAL and the lack of uniform diagnostic criteria have made it difficult to establish its cytogenetic features, although cytogenetic analysis reveals clonal
chromosomal abnormalities in 59-91% of patients. This article focuses on the significance of cytogenetic analysis in
ALAL supporting the importance of cytogenetic analysis in the pathogenesis, diagnosis, prognosis, follow up and treatment selection of
ALAL. It reviews in detail the types of
chromosomal aberrations, their molecular background, their correlation with immunophenotype and age distribution and their prognostic relevance. It also summarizes some novel
chromosome aberrations that have been observed only once. Furthermore, it highlights the ongoing and future research on
ALAL in the field of cytogenetics.