PDK4 and neoplasm: For another example, the drug tretinoin (also named as all trans retinoic acid) targeting three ISGs (PDK4, ICN1, RARRES1) was shown to dramatically reduce the presenter of immature myeloid cells, which promoted immunosuppression by increasing the production of reactive oxygen species, and thus contributed greatly to tumor progression (Kusmartsev et al., 2003; Wu et al., 2019).