TP53 mutations in newly diagnosed acute myeloid leukemia: Clinicomolecular characteristics, response to therapy, and outcomes

Abstract

Background: Mutations in the tumor protein 53 (TP53) gene predict a poor prognosis in patients with acute myeloid leukemia (AML).

Methods: Peripheral blood or bone marrow samples from 293 patients with newly diagnosed AML were analyzed with targeted, amplicon-based, next-generation sequencing-based mutation analysis.

Results: TP53 mutations were identified in 53 patients (18%; 45 were missense mutations). In 13 of the 53 patients, the most common pattern of amino acid substitution was a substitution of arginine to histidine on different codons. The clinical characteristics, pattern of mutations, response to different therapies, and outcomes of patients with AML-TP53-mutated (n = 53) versus wild-type TP53 (n = 240) were compared. TP53 mutations were significantly more likely in patients who had a complex karyotype; abnormalities of chromosome 5, 7, and 17; and therapy-related AML. Patients who had TP53-mutated AML had significantly lower incidence of mutations in Fms-like tyrosine kinase 3 (FLT3), rat sarcoma (RAS), and nucleophosmin (NPM1) and higher incidence of coexisting MPL mutations compared with those who had wild type TP53. The distribution of TP53 mutations was equal for both age groups (ages <60 years vs ≥60 years). TP53-mutated AML was associated with a lower complete remission rate (41% vs 57%; P = .04), a significantly inferior complete remission duration (at 2 years: 30% vs 55%; P = .001), and overall survival (at 2 years: 9% vs 24%; P ≤ .0001) irrespective of age or the type of treatment received (high-intensity vs low-intensity chemotherapy).

Conclusions: The type of treatment received did not improve outcomes in younger or older patients with TP53-mutated AML. These data suggest that novel therapies are needed to improve the outcome of patients with AML who have TP53 mutations. Cancer 2016;122:3484-3491. © 2016 American Cancer Society.

Keywords: acute myeloid leukemia (AML); adverse prognosis; biomarkers of resistance; complex karyotype; tumor protein 53 (TP53).

Figure 1. Distribution of mutations in patients with TP53 mutated AML (n=53)

The left-hand column lists the 28 genes that were tested in the panel. Each column represents a single patient and each colored bar indicates the presence of a mutation in the indicated gene. This illustrates the spectrum of coexistent mutations in patients with TP53 mutated AML.

Figure 2. Comparison of complete remission duration (CRD) in patients with/without TP53 mutation according to age (<60 vs >60 years)

A-B) The CR duration among patients with TP53-mutated AML was significantly inferior to those with wild type TP53 in both younger (<60 years; P=0.052) and older patients (>60 years; P=0.025).

Figure 3. Comparison of overall survival in patients with/without TP53 mutation regardless of therapy, by age (<60 vs >60 years)

A-B) The survival among patients with TP53-mutated AML was significantly inferior to those with wild type TP53 in both younger (<60 years; P=0.005) and older patients (>60 years; P=0.004).

Figure 4. Survival outcomes according to the type of treatment – intensive chemotherapy vs low intensity treatments

A) Patients with TP53-mutated AML who received intensive chemotherapy had a median survival of 6.8 months compared to 20.2 months in those with wild type-TP53 (P=0.06). B) Patients with TP53-mutated AML who received low intensity chemotherapy had a significantly inferior median survival of 6.7 months, compared to 12.5 months in those with wild type TP53 (P=0.007). C) Among the younger patients (<60 years age), survival was not significantly different when treated with intensive chemotherapy or low intensity chemotherapy. D) Among the older patients (>60 years age), survival was not significantly different after treatment with hypomethylating agents or with other low intensity therapies.