N(6)-methyladenosine RNA methylation regulators participate in malignant progression and have prognostic value in clear cell renal cell carcinoma

N(6)-methyladenosine (m6A) RNA methylation is the most prevalent type of mRNA modification; however, little is known about its function in clear cell renal cell carcinoma (ccRCC). The present study aimed to establish and validate a m6A-related risk signature as a prognostic factor for patients with ccRCC. Consensus clustering was used to divide patients with ccRCC from The Cancer Genome Atlas (TCGA) cohort (n=489) into three clusters (cluster 1/2/3) based on 19 m6A RNA methylation regulators. In addition, a m6A-related risk signature was constructed using TCGA data, and its accuracy was validated using data from the International Cancer Genome Consortium (n=91). The prognostic performance of the risk signature was evaluated by Kaplan-Meier analyses, least absolute shrinkage and selection operator Cox regression, multivariate Cox regression, receiver operating characteristic curves and nomograms. The results revealed that the majority of the 19 m6A RNA methylation regulators were differentially expressed among ccRCC stratified by different clinicopathological features. The cluster 1 group exhibited a higher frequency of metastasis and poorer overall survival compared with the cluster 2/cluster 3 group. The hallmarks of RNA metabolism, transcription misregulation in cancer and regulation of autophagy, were significantly enriched in the cluster 1 group. A m6A-related risk signature was constructed and validated with high prognostic accuracy for the prediction of 5-year survival and recurrence (area under the curve, 0.736 and 0.728, respectively). The present study also established robust nomograms for evaluating the risk of mortality and recurrence for patients with ccRCC (c-index, 0.783 and 0.819, respectively). The dysregulation of hub m6A RNA methylation regulator expression levels and m6A RNA methylation levels were also validated in multiple RCC cells using in vitro experiments. Taken together, the m6A RNA methylation regulators promoted the malignant progression of ccRCC and exhibited good performance in prognostic predictions. These results provided insight into the development of m6A-targeted treatments for ccRCC.