VHL and von Hippel-Lindau disease: The discovery of allelic deletions of the VHL gene in pancreatic NETs establishes NET as a distinct tumor type of VHL disease and provides direct molecular evidence for the involvement of the VH gene, according to Knudson et al., which predicts that each neoplasm should have a genotype consisting of one allele with an inherited germ-line mutation and loss of the second wild-type allele, which happen through chromosomal deletion.