A simple cytofluorimetric score may optimize testing for biallelic CEBPA mutations in patients with acute myeloid leukemia

Abstract

Acute myeloid leukemia with biallelic mutation of CEBPA(CEBPAdm AML) is a distinct good prognosis entity recognized by WHO 2016 classification. However, testing for CEBPA mutation is challenging, due to the intrinsic characteristics of the mutation itself. Indeed, molecular analysis cannot be performed with NGS technique and requires Sanger sequencing. The association of recurrent mutations or translocations with specific immunophenotypic patterns has been already reported in other AML subtypes. The aim of this study was the development of a specific cytofluorimetric score (CEBPA-dm score), in order to distinguish patients who are unlikely to harbor the mutation. To this end, the correlation of CEBPA-dm score with the presence of the mutation was analyzed in 50 consecutive AML patients with normal karyotype and without NPM1 mutation (that is mutually exclusive with CEBPA mutation). One point each was assigned for expression of HLA DR, CD7, CD13, CD15, CD33, CD34 and one point for lack of expression of CD14. OS was not influenced by sex, age and CEBPA-dm score. Multivariate OS analysis showed that CEBPA-dm (p<0.02) and FLT3-ITD (p<0.01) were the strongest independent predictors of OS. With a high negative predictive value (100%), CEBPA-dm score < 6 was able to identify patients who are unlikely to have the mutation. Therefore, the application of this simple score might optimize the use of expensive and time-consuming diagnostic and prognostic assessment in the baseline work up of AML patients. Highlights AML with CEBPA-dm is a distinct entity with an overall favorable outcome.  The evaluation of CEBPA-dm requires difficult and time consuming Sanger sequencing.  CEBPA-dm AML has a peculiar immunophenotypic signature.  The presence or the absence of CEBPA-dm can be predicted with our IF score.

Diagnostic Workup of Acute Myeloid Leukemia: What Is Really Necessary? An Italian Survey

“…According to the panelists, the execution of the molecular assays is mandatory. Sixty-five percent the panelists stated that the use of flow cytometry, even with CD7 assessment, is not reliable enough for the identification of biallelic CEBPA mutations ( 14 ).…”

Laboratory evaluation and prognostication among adults and children with CEBPA‐mutant acute myeloid leukemia

“…Use of this scoring system could facilitate identification of patients who warrant Sanger sequencing while effectively ruling out the need for CEBPA gene evaluation in other patients, which may be particularly useful for centers without in-house molecular hematology labs. 68 Lastly, some studies have described different methods of monitoring minimal residual disease (MRD) in CEBPA-mutant AML.…”

“…More importantly, scores less than 6 had 100% negative predictive value. Use of this scoring system could facilitate identification of patients who warrant Sanger sequencing while effectively ruling out the need for CEBPA gene evaluation in other patients, which may be particularly useful for centers without in‐house molecular hematology labs 68 …”

Immunophenotype distinctions of CEBPA mutation subtypes in acute myeloid leukemia

“…AML patients with CEBPA dm were associated with immunophenotypes of HLA-DR + CD7 + CD13 + CD14 À CD15 + CD33 + CD34 + . [14][15][16] However, the distinct immunophenotypes of CEBPA smB-ZIP mutations have not been characterized, especially when compared with those of CEBPA dm . Hence, we investigated the immunophenotypes of AML with CEBPA mutations and explored whether CEBPA dm-woBZIP should be considered as AML with mutated CEBPA or not based on immunophenotypes.…”

“…The mutation status of CEBPA correlates with immunophenotypes. AML patients with CEBPA dm were associated with immunophenotypes of HLA‐DR + CD7 + CD13 + CD14 − CD15 + CD33 + CD34 + 14–16 . However, the distinct immunophenotypes of CEBPA smBZIP mutations have not been characterized, especially when compared with those of CEBPA dm .…”