H2AX and sarcoma: To determine whether ATM and H2AX phosphorylation are increased in patients treated with an agent that induces ATM and H2AX phosphorylation in vitro, blood was drawn from three patients undergoing treatment for sarcoma before and at either 6, 14, and 24 h after infusion with the first cycle of doxorubicin (75 mg/m2) followed by ifosfamide (3 g/m2).