Frequency of MRD positivity at the different following time points. Percentage of patients without detectable MRD (□), detectable MRD below (), and above or equal to (▪) defined threshold values (10^-2 for day 11, 10^-4 for all other time points). Total number of patients varied at different time-points because sufficient follow-up material was not available from all patients for each time-point (frequency of low quality/quantity DNA was relatively high at time-point day 11 and day 44). ^*For time-points day 44 to week 52, 1 (week 16 and week 41), 2 (week 11, week 22, week 30, week 52), or 3 (day 44) MRD-positive samples could not be assigned to the MRD levels lower than 10^-4 or 10^-4 or higher because values below quantitative detection limit and range between quantitative detection limit and sensitivity limit spanned 10^-4.