PSMB6 and gastric adenocarcinoma: Conversely, a low expression of PSMB6 was observed in four specific types of tumors: Liver Hepatocellular Carcinoma (LIHC), Stomach Adenocarcinoma (STAD), Kidney Renal Clear Cell Carcinoma (KIRC), Kidney Chromophobe (KICH) (p < 0.05, Figure 1A).