BHD tumors represent a distinct class of renal cell carcinoma. A) Hierarchical clustering of renal tumor samples (BHDS, N = 6; ON, N = 11; CH, N = 12; CC, N = 10; PAP, N = 22; UR, N = 10) and non-diseased renal tissue (N = 12) using the expression data from the 1000 most variable genes. B) Unsupervised clustering of BHD, ON, and CH tumor samples using gene expression data from the 1500 most variable genes within this group. Bootstrap probability values are given for the major nodes. C) Expression of the distal convoluted tubule marker parvalbumin, PVALB, in the RCC tumor sample data used in A. D) qRT-PCR validation of expression of PVALB, along with two identified genes with high BHDS tumor-specific expression, cadherin 19 (CDH19) and regulator of G-protein signaling 20 (RGS20). BHD, N = 2; CC, N = 3; NO, N = 3; ON, N = 3. E) Gene expression heatmap displaying expression values after median centering for the fifty genes most up-regulated in BHDS-derived tumors compared to sporadic chromophobe RCC and renal oncocytoma from A. Abbreviations: NO, normal; ON, renal oncocytoma; CH, chromophobe RCC; CC, clear cell RCC; PAP, papillary RCC; UR, urothelial/TCC RCC.