The present study included two cohorts of patients: the TCGA cohort and the TZYY cohort. The TCGA cohort included 530 ccRCC patients, including 344 males and 186 females with a median age of 61 years (ranging from 26 to 90 years) at surgery. The RNA sequencing data of tumor tissue and clinicopathologic data for each patient were downloaded from TCGA database (TCGA-KIRC). The RNA sequencing data of 72 normal renal samples were also downloaded from TCGA database and were used as normal controls. The TZYY cohort included 241 ccRCC patients, including 157 males and 84 females with a median age of 59 years (ranging from 28 to 84 years) at surgery. The patients were hospitalized at Department of Urology, Taizhou Hospital, Wenzhou Medical University from 2004 to 2018 and were histologically confirmed ccRCC after partial or radical nephrectomy. All the patients had no other malignancy history and no history of anticancer therapy before surgery. Patients with mixed histological types were excluded. The clinical and pathological data of TZYY cohort patients were collected from medical records and follow-up records. Here, we defined the overall survival time (OS) as the time interval between surgery and the date of death or the last visit, and the disease-specific survival time (DSS) as the time interval between primary surgery and death from ccRCC or the last follow-up visit. For the analysis of disease-specific mortality, deaths as a result of other causes were censored. In the analysis of immunohistochemistry, 39 non-tumor tissue samples were used as controls. The informed consent has been obtained from all the participants. All research work with human participants was in accordance with the ethical standards of the responsible committee on human experimentation and with the Declaration of Helsinki. The present study was approved by the Ethics Committee of Taizhou Hospital (No. K20200821).