Identification of NDRG Family Member 4 (NDRG4) and CDC28 Protein Kinase Regulatory Subunit 2 (CKS2) as Key Prognostic Genes in Adrenocortical Carcinoma by Transcriptomic Analysis.

BACKGROUND Adrenocortical carcinoma (ACC) is an aggressive cancer with heterogeneous outcomes. In this study, we aimed to investigate genomic and prognostic features of ACC. MATERIAL AND METHODS Clinical, pathologic, and transcriptomic data from 2 independent datasets derived from ACC samples (TCGA-ACC dataset, GEO-GSE76021 dataset) were collected. Weighted gene co-expression network analysis (WGCNA) and survival analyses were performed to identify prognostic genes. Pathway analysis was performed for mechanistic analysis. xCell deconvolution was performed for tumor microenvironment analysis. RESULTS In the TCGA-ACC cohort, WGCNA identified a prognostic module of 5408 genes. Differential expression analysis identified 1969 genes that differed in expression level between long-term and short-term survivors. Univariate Cox regression model analysis identified 8393 genes with prognostic value. The intersection of these gene sets included 820 prognostic genes. Similar protocols were performed for the GSE76021 dataset, and 5 candidate genes were identified. Further intersection of these genes finally identified NDRG4 and CKS2 as key prognostic genes. Multivariate Cox regression model analysis validated the prognostic value of NDRG4 (HR=0.61, 95% CI 0.46-0.80) and CKS2 (HR=2.52, 95% CI 1.38-4.60). Moreover, NDRG4 and CKS2 expression predicted survival in patients treated with mitotane (P<0.001). Further mechanism exploration found an association between CKS2 and DNA mismatch repair pathways. Moreover, NDRG4 positively correlated with CD8⁺ T cell infiltration, while CKS2 negatively correlated with it. CONCLUSIONS We identified NDRG4 and CKS2 expression as key prognostic genes in ACC, which may help in risk stratification of ACC. Moreover, a close relationship was found between CKS2 and mismatch repair pathways. Moreover, immune cell infiltration differed according to NDRG4 and CKS2 expression.