Chemotherapy regimens. DAT 3 + 7 indicates daunorubicin 45 mg/m² intravenous push (over 15 minutes) on days 1, 2, and 3; Ara-C 100 mg/m² continuous 24-hour intravenous infusion on days 1-7 (168 hours); and thioguanine 100 mg/m² by mouth, single daily dose on days 1-7. HDAT 3 + 7 indicates daunorubicin 45 mg/m² intravenous push (over 15 minutes) on days 1, 2, and 3; Ara-C 1 g/m² intravenous 1-hour infusion every 12 hours for 7 days (14 doses); and thioguanine 100 mg/m² by mouth, single daily dose on days 1-7. HA indicates Ara-C 1 g/m² intravenous 1-hour infusion every 12 hours for 5 days (10 doses). EM - CSA indicates etoposide 100 mg/m² intravenous 45 minutes-1 hour infusion on days 1-5 and mitoxantrone 10 mg/m² intravenous 30-minute infusion on days 1-4. EM + CSA indicates etoposide 100 mg/m² intravenous 45 minutes-1 hour infusion on days 1-5; mitoxantrone 10 mg/m² intravenous 30-minute infusion on days 1-4; and CsA 10 mg/kg intravenous 2-hour loading dose followed by 30 mg/kg continuous infusion for 98 hours (total 100 hours).