PGD and infection: To better understand the influence of HIF-1α on PGD expression in GIST cells, we downregulated HIF-1α expression in GIST-T1R and GIST-882R cells by lentivirus infection and verified the altered expression of HIF-1α in these GIST cell lines by western blotting (Fig. 5g and Supplementary Fig. 4B).