CD274 and neoplasm: The high-frequency keywords of PROC research (Figures 7A, B) included chemotherapy, expression, apoptosis, activation, tumor microenvironment, PARP inhibitors (Olaparib, niraparib, rucaparib), pazopanib, maintenance therapy, BRCA1/2, PD-L1 expression, etc., which were regarded as the hotspots in PROC research.