Quantitative NPM-ALK PCR results in bone marrow according to the outcome of the ALCL patients. Normalized NPM-ALK copy numbers (copies NPM-ALK/10⁴ copies ABL) in bone marrow of the 74 patients with either a negative qualitative BM PCR (= 0 copies NPM-ALK) or a positive qualitative BM PCR using quantitative PCR results. TRM indicates treatment related mortality; sec mal, second malignancy.