We then used TRRUST to predict the potential upstream transcription factors of all MHCs and found that CIITA, RFX5, RFXANK, and RFXAP were the most likely transcription factors (Supplementary Table S3), and the expression of FASN was significantly negatively correlated with MHC class II transcriptional activators CIITA and RFXANK in a variety of cancers (Figure 5E), which is consistent with the findings in MHCs. The gene discussed is FASN; the disease is cancer.