CCAAT/enhancer binding protein-alpha polymorphisms occur more frequently than mutations in acute myeloid leukemia and exist across all cytogenetic risk groups and leukemia subtypes

CEBPA-bZip mutations are associated with favorable prognosis in de novo AML: a report from the Children's Oncology Group

Biallelic CEBPA mutations are associated with favorable outcomes in acute myeloid leukemia (AML). We evaluated the clinical and biologic implications of CEBPA-basic leucine zipper (CEBPA-bZip) mutations in children and young adults with newly diagnosed AML. CEBPA-bZip mutation status was determined in 2958 patients with AML enrolled on Children's Oncology Group trials (NCT00003790, NCT0007174, NCT00372593, NCT01379181). Next-generation sequencing (NGS) was performed in 1863 patients (107 with CEBPA mutations) to characterize the co-occurring mutations. CEBPA mutational status was correlated with disease characteristics and clinical outcomes. CEBPA-bZip mutations were identified in 160 (5.4%) of 2958 patients, with 132 (82.5%) harboring a second CEBPA mutation (CEBPA-double-mutated [CEBPA-dm]) and 28 (17.5%) had a single CEBPA-bZip only mutation. The clinical and laboratory features of the 2 CEBPA cohorts were very similar. Patients with CEBPA-dm and CEBPA-bZip experienced identical event-free survival (EFS) of 64% and similar overall survival (OS) of 81% and 89%, respectively (P = .259); this compared favorably to EFS of 46% and OS of 61% in patients with CEBPA-wild-type (CEBPA-WT) (both P < .001). Transcriptome analysis demonstrated similar expression profiles for patients with CEBPA-bZip and CEBPA-dm. Comprehensive NGS of patients with CEBPA mutations identified co-occurring CSF3R mutations in 13.1% of patients and GATA2 mutations in 21.5% of patients. Patients with dual CEBPA and CSF3R mutations had an EFS of 17% vs 63% for patients with CEBPA-mutant or CSF3R-WT (P < .001) with a corresponding relapse rate (RR) of 83% vs 22%, respectively (P < .001); GATA2 co-occurrence did not have an impact on outcome. CEBPA-bZip domain mutations are associated with favorable clinical outcomes, regardless of monoallelic or biallelic status. Co-occurring CSF3R and CEBPA mutations are associated with a high RR that nullifies the favorable prognostic impact of CEBPA mutations.

The significance of c.690G>T polymorphism (rs34529039) and expression of the CEBPA gene in ovarian cancer outcome

The CEBPA gene is known to be mutated or abnormally expressed in several cancers. This is the first study assessing the clinical impact of CEBPA gene status and expression on the ovarian cancer outcome. The CEBPA gene sequence was analyzed in 118 ovarian cancer patients (44 platinum/cyclophosphamide (PC)-treated and 74 taxane/platinum (TP)-treated), both in tumors and blood samples, and in blood from 236 healthy women, using PCR-Sanger sequencing and Real-Time quantitative PCR (qPCR)-based genotyping methods, respectively. The CEBPA mRNA level was examined with Reverse Transcription quantitative PCR (RT-qPCR). The results were correlated to different clinicopathological parameters. Thirty of 118 (25.4%) tumors harbored the CEBPA synonymous c.690G>T polymorphism (rs34529039), that we showed to be related to up-regulation of CEBPA mRNA levels (p=0.0059). The presence of the polymorphism was significantly associated with poor prognosis (p=0.005) and poor response to the PC chemotherapy regimen (p=0.024). In accordance, elevated CEBPA mRNA levels negatively affected patient survival (p<0.001) and tumor response to the PC therapy (p=0.014). The rs34529039 SNP did not affect the risk of developing ovarian cancer. This is the first study providing evidence that the c.690G>T, p.(Thr230Thr) (rs34529039) polymorphism of the CEBPA gene, together with up-regulation of its mRNA expression, are negative factors worsening ovarian cancer outcome. Their adverse clinical effect depends on a therapeutic regimen used, which might make them potential prognostic and predictive biomarkers for response to DNA-damaging chemotherapy.

Molecular evaluation of CEBPA gene mutation in normal karyotype acute myeloid leukemia: a comparison of two methods and report of novel CEBPA mutations from Indian acute myeloid leukemia patients

BACKGROUND AND AIM

Mutation in the CAAT/enhancer binding protein-α (CEBPA) gene has been reported as being one of the common genetic abnormalities in acute myeloid leukemia (AML) and is associated with a good clinical outcome. We intend to explore the prevalence of CEBPA mutations and evaluate the efficacy of fragment and sequencing analysis methods for CEBPA mutation detection in Indian AML patients.

MATERIALS AND METHODS

The coding region of the CEBPA gene was screened in 36 normal karyotype AML patients by fragment analysis and direct sequencing.

RESULTS

We identified five CEBPA sequence variations in three patient samples (8.3%) by direct sequencing analysis, of which three were novel mutations. These mutations were clustered mostly in the TAD1 and basic region leucine zipper region of the CEBPA protein. Six cases demonstrated a previously reported polymorphism. Two of the three positive cases showed double mutations, and one case had a single mutation. All five mutations were also detected by fragment analysis, indicating a sensitivity of 100% (5/5). No correlation with clinical parameters including age, sex, white blood cell count, hemoglobin, and platelet count between patients with and without mutation was observed. Interestingly, CEBPA mutations were significantly higher in patients with WT1 mutation, while no correlation with FLT3 and NPM1 was observed.

CONCLUSION

We report for the first time the frequency of CEBPA mutation from an Indian patients (8.3%). The identification of novel CEBPA mutations added new insights into the genetic heterogeneity of AML. Our result suggests that the optimal approach for detecting CEBPA mutations in AML can be a combination of fragment analysis and direct sequencing.