Progression free survival of myeloma patients who become IFE-negative correlates with the detection of residual monoclonal free light chain (FLC) by mass spectrometry. - Giles HV; Drayson MT; Kishore B; Pawlyn C; Kaiser M; Cook G; de Tute R; Owen RG; Cairns D; Menzies T; Davies FE; Morgan GJ; et al. (Blood cancer journal, 2024)