HGSOC tumor tissue microarrays (TMA) were kindly provided by Dr. Benjamin G Bitler from The University of Colorado (COMIRB# 17-7788). Detailed information on the tumors contained on the TMA has been published previously (32 (link),33 (link)). IHC was performed using the Dako EnVision+ system following the manufacturer’s instructions. Briefly, the sections were dewaxed, rehydrated and immersed in 3% hydrogen peroxide in methanol to quench endogenous peroxidase activity. Antigen retrieval was performed in sodium citrate buffer (Thermo Fisher, #005000) and boiled for 45 min. The sections were incubated with blocking buffer for 1 h, primary antibody against TRIM28 (Abcam, #ab10484, RRID:AB_297223), SETDB1 (Biological Novus, #NBP2-20322) or PD-L1 (CST, #13684S, RRID:AB_2687655) at 4°C overnight and secondary antibody for 1h (DAKO, #K4011). Counterstaining was performed using Mayer’s Hematoxylin (Dako, #3309S). Expression of the stained markers was scored using a histologic score (H score). Based on the H scores, Kaplan-Meier survival curves were generated for SETDB1 and TRIM28 high and low patient groups using GraphPad Prism 7 (GraphPad) software. P value was calculated by log-rank test.