1 Supplementary Fig. 1 – Flowchart of the conducted statistical analyses. ccRCC = clear cell renal cell carcinoma; CSS = cancer-specific survival. 479 samples in TCGA ccRCC cohort (https://tcga-data.nci.nih.gov/tcga/) [19] with • available RNA-Seq data • complete CSS information • non-missing data for important clinicopathological features 8 SAGE libraries from [23] representing gene expression in human nephron regions Identification of 97 marker genes distinguishing nephron regions (Fig. S2) Interprofile correlation between tumor samples and nephron regions Consensus clustering based on interprofile correlations (Fig. S3A) Removal of 16 non-ccRCC samples (Table S2) 463 ccRCC samples Introduction of nephron-region-scores (columns of Fig. 1A) Re-clustering based on interprofile correlations (Fig. 1A) Association of CSS to nephron-region-scores Kaplan-Meier analysis of clusters for CSS (Fig. S4) S3-score constitutes minimal and sufficient Cox model Group assignment of ccRCC samples based on S3score to facilitate clinical application (Fig. 1B): • S3-score cut-off: -0.167 • 322 ccRCC samples in “high” group (above cut-off) • 141 ccRCC samples in “low” group 2 Supplementary Fig. 2 – Heat map of the selected 97 genes and their expression in different parts of the normal human nephron (expression data from Cheval et al [23]). Glomeruli (Glom), initial and terminal part of proximal tubule (S1/S3), medullary and cortical thick ascending limbs of the loop of Henle (mTAL/cTAL), distal convoluted tubules (DCT), and cortical as well as outer medullary collecting ducts (CCD/OMCD). 3 Supplementary Fig. 3 – Clustering of renal cell carcinoma (RCC) tumours by means of gene expression correlation between profiles of tumours and profiles of human nephron cell types. (a) Interprofile Spearman rank correlation coefficients (IPCs) were calculated using 97 genes that differentiate nephron regions (glomeruli [Glom], initial and terminal part of proximal tubule [S1/S3], medullary and cortical thick ascending limbs of the loop of Henle [mTAL/cTAL], distal convoluted tubules [DCTs], cortical and outer medullary collecting ducts [CCD/OMCD]). The heat map shows z scores obtained by centering and standardising the IPC per the Cancer Genome Atlas (TCGA) sample. Samples were clustered per tumour entity using a resampling-based consensus clustering approach. Resulting clusters are color coded (see color bar on the left) (b) Somatic copy number variations of RCC tumours (samples are arranged in the same order as above). GISTIC2 gene-level copy number estimates represent homozygous deletion (−2), single copy deletion (−1), diploid normal copy (0), low-level copy number (1), and high-level copy number amplification (2). Grey color indicates missing CNV data. ccRCC = clear cell renal cell carcinoma; chRCC = chromophobe renal cell carcinoma; pRCC = papillary renal cell carcinoma. 4 Supplementary Fig. 4 – Kaplan-Meier curves showing cancer-specific survival of (a) clear cell renal cell carcinoma clusters and (b) papillary renal cell carcinoma clusters. Colours of the lines correspond to colours of cluster analyses given in Figure 1a of the article. The clusters were identified using a resampling-based consensus clustering approach. CI = confidence interval; HR = hazard ratio. 5 Supplementary Fig. 5 – Distribution of patient characteristics and clinicopathologic parameters in the high and low groups, as identified by the S3-score (cut-off: −0.167). Associated p values are shown in Supplementary Table 3. 6 Supplementary Fig. 6 – Cancer-specific survival of clear cell renal cell carcinoma (ccRCC) tumours with different tumour stages predicted by the S3-score. KaplanMeier curves showing cancer-specific survival of ccRCC patients with stage I (n = 221), stage II/III (n = 164), and stage IV (n = 78), respectively, for high and low groups, as identified by the S3-score. 7 Supplementary Fig. 7 – Cancer-specific survival of clear cell renal cell carcinoma (ccRCC) tumours predicted by the S3-score. Kaplan-Meier curves showing cancerspecific survival of ccRCC patients with different stage, size, grade, and necrosis scores for high and low groups, as identified by the S3-score. 8 Supplementary Fig. 8 – S3-score significantly improves established prediction scores. Chi-square statistic values depict the improvement of the model likelihood when S3score (red) and ClearCode34 (CC34) signature (blue) are sequentially added to the Cox model, initially including only the SSIGN score. The chi-square statistic comparing the initial model with the null model is given as a baseline value (177.73). *p < 0.05, **p < 0.01, ***p < 0.001. 9 Supplementary Fig. 9 – Intratumour heterogeneity of the S3-score across different tumour regions of 10 clear cell renal cell carcinoma samples. Color codes are defined by median S3-score per patient, indicating membership to high or low group with good or poor prognosis, as identified by the S3-score. S3-score cut-off (−0.167) is represented by the dashed blue line. 10 Supplementary Fig. 10 – Scatter plot of the S3-score and S1-score in the Cancer Genome Atlas clear cell renal cell carcinoma cohort (n = 463) along with the Spearman rank correlation coefficient.