After 18 days of treatment, the growth of ATF4-expressing xenografts in BTZ-treated animals remained nearly completely inhibited, whereas the growth of xenografts of vehicle-treated animals was significantly more pronounced (median tumor volume increase 5.3% ± 27.8% versus 549.3% ± 133.5%; P = 0.001; Figure 1A). This evidence concerns the gene ATF4 and neoplasm.