This modified promoter, termed 2xAARE-YB, contains six AARE repeats derived from the TRIB3 promoter and was validated for its ability to induce ATF4-dependent GFP expression in T cells infiltrating 3D spheroid models that mimic the tumor microenvironment, which is characterized by AA deprivation and hypoxia [37–39]. Here, ATF4 is linked to neoplasm.