MIF and cancer: Sulforaphane's sulfoxide moiety can be replaced with a ketone without affecting activity.101 was reported to identify over 100 protein targets in HEK293 cells by mass spectrometry (MS); however, only two targets of this probe have been validated as genuine sulforaphane targets (macrophage migration inhibitory factor (MIF) and AKAP149), and profiling was not performed in cancer cell lines.10 We therefore synthesised 1 alongside a novel probe 2 (Fig. 1a) with greatly reduced steric encumbrance around the electrophilic warhead.