With CCK-8 and colony formation assays examining the proliferation of GC cells, we discovered that the absorbance at 450 nm in GC cells was markedly declined after the transfection with pcDNA3.1/GATA6-AS1 in comparison with negative control (Figure 2(b), left panels), while that was significantly increased in the HGC-27 cells transfected with sh-GATA6-AS1#1 and sh-GATA6-AS1#2 compared with the sh-NC group (Figure 2(b), right panel), indicating that overexpressed GATA6-AS1 restrains cell viability while GATA6-AS1 depletion promotes that in GC. This evidence concerns the gene PTGDR and gastric cancer.