Biallelic TET2 mutations confer sensitivity to 5′-azacitidine in acute myeloid leukemia

Precision medicine can significantly improve outcomes for patients with cancer, but implementation requires comprehensive characterization of tumor cells to identify therapeutically exploitable vulnerabilities. Here, we describe somatic biallelic TET2 mutations in an elderly patient with acute myeloid leukemia (AML) that was chemoresistant to anthracycline and cytarabine but acutely sensitive to 5 '-azacitidine (5 '-Aza) hypomethylating monotherapy, resulting in long-term morphological remission. Given the role of TET2 as a regulator of genomic methylation, we hypothesized that mutant TET2 allele dosage affects response to 5 '-Aza. Using an isogenic cell model system and an orthotopic mouse xenograft, we demonstrate that biallelic TET2 mutations confer sensitivity to 5 '-Aza compared with cells with monoallelic mutations. Our data argue in favor of using hypomethylating agents for chemoresistant disease or as first-line therapy in patients with biallelic TET2-mutated AML and demonstrate the importance of considering mutant allele dosage in the implementation of precision medicine for patients with cancer.

Automated summary

Precision medicine is important in improving outcomes for cancer patients, and in this study, it was found that elderly patients with acute myeloid leukemia (AML) who had somatic biallelic TET2 mutations were resistant to certain chemotherapies but sensitive to 5'-azacitidine (5'-Aza) hypomethylating monotherapy. Experimental evidence showed that cells with biallelic TET2 mutations were more sensitive to 5'-Aza compared to cells with monoallelic mutations. This study suggests the potential use of hypomethylating agents as a treatment option for chemoresistant AML patients with biallelic TET2 mutations and highlights the importance of considering mutant allele dosage in precision medicine for cancer patients.