PSMB9 and cancer: The gene co-expression network of BATF2 mRNA in Pan-cancer was plotted using Coexpedia, as shown in Fig. 4A. Finally, 98 genes were predicted to interact with BATF2 mRNA, and the co-expression of BATF2 with TAP1, STAT1, and PSMB9 was the most critical in the occurrence and development of BC (Fig. 4B).