This type of linker has shown high efficacy in certain tumor models; for example, ado-trastuzumab emtansine (Kadcyla®), which conjugates the anti-HER2 antibody trastuzumab to the maytansinoid DM1 via a non-cleavable thioether linker, is approved for the treatment of HER2-positive breast cancer. Here, ERBB2 is linked to breast cancer.