In conclusion, real-time quantification of TEL-AML1/beta-actin kinetics distinguishes distinct molecular response groups, and provides indications capable of directing therapeutic interventions for patients with TEL-AML1+ ALL.     ///    "In relapsed ALL, TEL-AML1/beta-actin decrease was generally less pronounced at corresponding time points, and conversion to TEL-AML1 negativity was observed in 40% of patients. "    ///    "In initial ALL, TEL-AML1/beta-actin decrease was > or =10(5)-fold in 50% of patients after induction therapy (day 33) and stayed TEL-AML1-negative throughout therapy, which suggested high sensitivity of leukemic cells to antineoplastic therapy. "