IGH/MYC Translocation Associates with BRCA2 Deficiency and Synthetic Lethality to PARP1 Inhibitors.

Burkitt lymphoma/leukemia cells carry t(8;14)(q24;q32) chromosomal translocation encoding IGH/MYC, which results in the constitutive expression of the MYC oncogene. Here, it is demonstrated that untreated and cytarabine (AraC)-treated IGH/MYC-positive Burkitt lymphoma cells accumulate a high number of potentially lethal DNA double-strand breaks (DSB) and display low levels of the BRCA2 tumor suppressor protein, which is a key element of homologous recombination (HR)-mediated DSB repair. BRCA2 deficiency in IGH/MYC-positive cells was associated with diminished HR activity and hypersensitivity to PARP1 inhibitors (olaparib, talazoparib) used alone or in combination with cytarabine in vitro Moreover, talazoparib exerted a therapeutic effect in NGS mice bearing primary Burkitt lymphoma xenografts. In conclusion, IGH/MYC-positive Burkitt lymphoma/leukemia cells have decreased BRCA2 and are sensitive to PARP1 inhibition alone or in combination with other chemotherapies.Implications: This study postulates that IGH/MYC-induced BRCA2 deficiency may predispose Burkitt lymphoma cells to synthetic lethality triggered by PARP1 inhibitors.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/15/8/967/F1.large.jpgMol Cancer Res; 15(8); 967-72. ©2017 AACR.