TCGA analysis

The transcriptome profiling and corresponding clinical information for RCC (including renal clear cell carcinoma, renal papillary cell carcinoma, kidney chromophobe and kidney sarcoma) was retrieved from the open-source TCGA database (http://xena.ucsc.edu/welcome-to-ucsc-xena/). All the following data processing was implemented by R software. Original gene expression data was normalized using the trimmed mean of M-values method and the edgeR package was applied to figure out the differentially expressed genes (DEGs). Genes with the absolute value of Log₂ fold change ≥ 1.0 and false discovery rate (FDR) value < 0.05 were regarded as statistically significant.

Patients were divided into discover cohort and validation cohort. In the discover cohort, 30 patients with biopsy-proven RCC were enrolled from June 2018 to January 2019. Among the 30 RCC specimens, 21 of them had the corresponding normal portion of renal tissues obtained from the opposite pole of RCC. In the validation cohort, 40 patients with biopsy-proven RCC were enrolled from February 2023 to April 2023. All the samples were obtained from surgical operations performed in the Department of Urology, The First Affiliated Hospital of Zhengzhou University and examined by pathology experts to establish a definitive diagnosis. This study was approved by the Institutional Ethics Review Board of The First Affiliated Hospital of Zhengzhou University, and informed consent were obtained from all participants. All methods were carried out in accordance with relevant guidelines and regulations.