In a 6-year-child with ALL relapse, most common site:

a. Bone marrow(Ref: Nelson's 20/e p 2439-2441, Ghai 8/e p 599)Infants with ALL, and patients with t(4;11), have a higher risk of relapse despite intensive therapyHigher levels of MRD (>0.01%) present at end of induction suggest a poorer prognosisRelapse occurs in the bone marrow in 15-20% of patients with ALL and carries the most serious implications