In addition, it is clear that there are multiple mechanisms present in cancer cells that may provide avenues for resistance to ASCT2 inhibition, such as those seen for glutaminase inhibitors (Dos Reis et al, 2019; Singleton et al, 2020), as well as the potential for upregulation of alternative glutamine transporters (Bröer et al, 2019). This evidence concerns the gene GLS and cancer.