PML and acute promyelocytic leukemia: In the field of hematology, the use of the matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) method and complement C3f-desArg and its derivatives has been identified to correlate with MRD levels in patients with PML/RARα-positive acute promyeloid leukemia (APL) (18).