To examine whether Notch1 activity, i.e. signaling through the Notch1 receptor, also was elevated in ccRCC, we stained a tissue micro array (TMA) with 56 ccRCC samples and 4 samples with normal renal tissue, using an antibody raised against the intracellular part of cleaved human Notch1 (NICD1) (Fig. 1A–C). This evidence concerns the gene NOTCH1 and nonpapillary renal cell carcinoma.