ID1 expression associates with other molecular markers and is not an independent prognostic factor in cytogenetically normal acute myeloid leukaemia

Summary In acute myeloid leukaemia with normal karyotype ( CN ‐ AML ), gene mutations (e.g. NPM 1 , FLT 3 , CEBPA ) as well as deregulated gene expression affect outcome. High expression of ID 1 was described as a negative prognostic factor. We have shown that CEBPA regulates ID 1 expression. Therefore, we analysed the prognostic impact of ID 1 expression in 269 patients (aged 16–60 years) with CN ‐ AML in the context of other molecular markers, particularly CEBPA mutations. ID 1 high status was an independent negative prognostic factor for overall survival ( OS ) in multivariate analysis when analysed together with age, extramedullary disease, platelets, expression of BAALC and WT 1 , FLT 3 ‐internal tandem duplication, NPM 1 , WT 1 single nucleotide polymorphism rs16754 and IDH 1 . ID 1 expression was higher in CEBPA wildtype patients than in patients with monoallelic CEBPA mutations and these patients showed higher ID 1 expression compared to patients with biallelic CEBPA mutations. Thus, when CEBPA mutations were considered, ID 1 expression lost its prognostic impact. Likewise, the negative impact of ID 1 high status on relapse‐free survival ( RFS ) was lost when CEBPA mutations were included in the analysis. In CEBPA wildtype patients, ID 1 expression had no impact on complete remission‐rate, OS or RFS . In conclusion, CEBPA mutations seem to deregulate ID 1 expression. Therefore, ID 1 expression is not an independent prognostic factor in CN ‐ AML .