PSMC4 and neoplasm: Across all six PSMC genes, only PSMC2 and PSMC4 exhibited a significant correlation with lymph node metastasis stage and neoplasm disease stage (p < .05, Supplementary Figure S3A), and groups with PSMC2 and PSMC4 overexpression had a higher number of patients with advanced lymph node metastasis and neoplasm disease stages.