Pathophysiology
VHL is an inherited disorder characterized by the formation of both benign and malignant tumors and cysts in various parts of the body. Tumors may occur during young adulthood; however, the signs and symptoms of VHL can develop throughout life. VHL is an autosomal dominant hereditary cancer syndrome caused by mutations in the VHL tumor suppressor gene located on chromosome 3. VHL is estimated to occur in 1 of every 30,000–40,000 individuals (Lindor, McMaster, Lindor, & Greene, 2008).VHL follows Knudson's (1996) "two-hit" model for carcinogenesis. In inherited cases, the first hit is a VHL germline (inherited) mutation. The second hit is a somatic (acquired) mutation. Tumor formation requires mutations in both VHL alleles in the somatic tissue. Individuals with VHL have a predisposition for developing renal cell carcinomas, pheochromocytomas, central nervous system hemangioblastomas, retinal hemangioblastomas, endolymphatic sac tumors, and renal and pancreatic cysts (see Table 1). Genetic (DNA) testing for germline VHL mutations costs less than $1,000, often is covered by insurance, and is capable of detecting about 100% of all described VHL mutations (Frantzen, Links, & Giles, 2009; Kaelin, 2007). When the clinical diagnosis of VHL is confirmed by germline genetic testing, implementation of appropriate screening can significantly decrease a patient's morbidity and mortality.
Oncol Nurs Forum. 2012;39(6):533-536. © 2012 Oncology Nursing Society
