Cytokeratin 7 (encoded by KRT7/CK7) is found in the majority of type 1 papillary renal cell carcinomas and chromophobe renal cell carcinomas, and its expression profile alteration is particularly associated with tumorigenesis of primary adenocarcinoma of the small intestine (Chen and Wang, 2004; Mazal et al. 2005). The gene discussed is KRT7; the disease is hereditary papillary renal cell carcinoma.