It should also be noted that although we have discussed the inhibitory activity of SLURP-1 via orthosteric or allosteric binding sites in nAChRs, the data in the literature suggest that, in certain cancer cell lines, rSLURP-1 acts not only on the α7 nAChR but also targets some receptors not belonging to the family of Cys-loop ligand-gated ion channels, opening new lines to potential drugs [9,39]. Here, SLURP1 is linked to cancer.