EIF2AK4 and prostate cancer: To further test the GCN2/SLC3A2 (4F2) model, we derived a gene signature from GCN2-dependent transcripts from our RNA-seq analysis and measured a significant correlation with SLC3A2 (4F2) expression (r = 0.53, p < 0.0001) using a cohort of prostate cancer patients (PRAD) from the TCGA database (Figure 7H).