Immunohistochemistry (Figure S4A, Supporting Information) and western blotting (Figure 3G) analyses demonstrated that ATF4 knockdown suppressed the expression of the glutamine transporter alanine, serine, and cysteine‐preferring transporter 2 (ASCT2), thereby affecting glutamine uptake and utilization in tumor cells during glutamine restriction (Figure 3H). Here, ATF4 is linked to neoplasm.