Effects of gentisyl alcohol on suppressing proliferation in human ovarian cancer cells. (A,B) Proliferation assays were performed on gentisyl alcohol-treated ES2 and OV90 cells in dose-dependent manners. The results are presented as a bar graph indicating percentages relative to vehicle-treated cells as the control. (C,D) Microscopy photo of ES2 and OV90 cells expressing proliferating cell nuclear antigens (PCNAs) emitting green fluorescence in the nuclei. 4′,6-diamidino-2-phenylindole (DAPI, blue) was used to counter-stain the nuclei co-localized with PCNAs. The scale-bar represents 20 μm (the first and third horizontal panels) and 10 μm (the second and fourth horizontal panels). Asterisks indicate significant effects on treated cells compared to those on vehicle-treated cells (* p < 0.05, ** p < 0.01, and *** p < 0.001).