In an in vivo study, responsiveness of mice bearing TC-71 Ewing sarcoma tumors to a combination of talazoparib and temozolamide was correlated with decreased levels of total or cleaved PARP and increases in γ–H2AX; however, tumors that were resistant to the combination treatment were shown to have some cleaved PARP but no decrease in total or cleaved PARP, or increases in γ–H2AX (38). The gene discussed is PARP1; the disease is Ewing sarcoma.