This confirmed that marked cells in Vhljae.KO/pjr.fl mice were functionally Vhl-null, and that tdTomato-positive cells in Vhlwt/pjr.fl mice were Vhl-haplosufficient, consistent with the designation of VHL as a classical tumor suppressor needing biallelic inactivation to promote oncogenesis. This evidence concerns the gene VHL and neoplasm.