HINT1 and breast cancer: [44] and [45]), all benzyl derivatives act as efficient inhibitors in model biological systems (RRL and zebrafish embryo cells) compared with their methylated counterparts [43–45]. bn7GMP, applied in lung, breast cancer and malignant mesothelioma cells as a membrane-permeable prodrug called 4Ei-1 [which is converted into the active compound in cells—bn7GMP—by the histidine triad nucleotide-binding protein 1 (Hint1)], suppresses malignant phenotypes and chemosensitizes cells to non-toxic levels of the cytotoxic drugs such as gemcitabine or pemetrexed [46,47].