Expression of Hypoxia Inducible Factor-1α and 2α in Genetically Distinct Early Renal Cortical Tumors

Purpose: The role of the HIF class of transcription factors has been implicated to be a critical step in clear cell kidney tumorigenesis. To assess if HIF over expression is a prominent feature of other renal cell carcinoma histological subtypes we characterized the expression of HIF-1α and HIF-2α in genetically distinct early renal cortical tumors.Materials and Methods: Nascent renal tumors of distinct histology from patients with a hereditary renal tumor syndrome were characterized for HIF expression using high amplification immunohistochemistry. In addition, indirect immunofluorescence and confocal microscopy were used for subcellular localization of HIF-1α and 2α in clear cell renal carcinoma cells.Results: Clear cell RCC tumors from patients with von Hippel-Lindau disease strongly expressed HIF-1α and HIF-2α (10 of 12 and 12 of 12 tumors, respectively). Chromophobe tumors from patients with Birt-Hogg-Dube syndrome expressed predominantly HIF-2α with weaker HIF-1α expression (12 of 12 and 6 of 12 tumo...