Although significant downregulation was observed in the mRNA levels of SLC3A2, SLC7A1, and SLC7A7, only the protein expression of SLC3A2 was consistently diminished in a dose‐dependent manner across the PTCL cell lines upon quinacrine treatment (Figure 2J,K, and Figure S2K, Supporting Information). This evidence concerns the gene SLC7A1 and mature T-cell and NK-cell non-Hodgkin lymphoma.