EIF4E and cancer: Additionally, the Taunton and Shoichet labs described the development of a virtual library of “make on demand” aryl sulfonyl fluorides to target the eukaryotic translation initiation factor 4E (eIF4E) protein, which has been associated with cancer cell growth and metathesis.77 The eIF4E protein lacks cysteine residues near the cap binding site and therefore the authors had the goal of accessing a noncatalytic lysine residue, to develop a covalent probe.