However, one study showed that the HDAC3/STAT3 pathway transcriptionally regulates PD-L1 expression in pancreatic ductal adenocarcinoma, and HDAC3 inhibitors reduce the protein and mRNA levels of PD-L1 in pancreatic cancer cells (Hu et al., 2019). The gene discussed is HDAC3; the disease is pancreatic ductal adenocarcinoma.