TP53 and neoplasm: While it is not possible to assay for loss of p53 protein by immunohistochemistry due to the fact that p53 is not detectable in normal kidney cells, PCR genotyping of laser capture micro-dissected simple cysts, atypical cysts and neoplasms demonstrated that the recombined Trp53 and Vhl alleles were present in cells in these lesions (Supporting Information Fig 3).