SLC7A5 also mediates the transport of thyroid hormones and hormone precursors across the cell membrane, L-DOPA across the blood-brain barrier, L-leucine across the blood-retinal barrier, amino acid-polyamine-organocation superfamily pharmaceutical drugs, toxic methylmercury, 3-(18)F-l-α-methyl-tyrosine PET probe in cancer imaging, and others [7–11]. Here, SLC7A5 is linked to cancer.