Somatic Hits in Polycystic Liver Diseases
Wybrich R Cnossen and Joost PH Drenth*
Radboud UMC, Department of Gastroenterology and Hepatology, Institute for Genetic and Metabolic Disease, Nijmegen, The Netherlands
- *Corresponding Author:
- Joost PH Drenth
Department of Gastroenterology and Hepatology
Radboud University Medical Center
P.O. Box 9101, 6500 HB Nijmegen
E-mail: [email protected]
Received date: November 20, 2013; Accepted date: December 26, 2013; Published date: December 31, 2013
Citation: Cnossen WR, Drenth JPH (2013) Somatic Hits in Polycystic Liver Diseases. J Carcinogene Mutagene 5:154. doi: 10.4172/2157-2518.1000154
Copyright: © 2013 Cnossen WR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Polycystic Liver Disease (PLD) encompasses a number of disorders with the development of multiple cysts distributed throughout the liver either focally or equally. Hepatic cysts are fluid-filled cavities lined by benign epithelium. PLD is the major phenotype of isolated Polycystic Liver Disease (PCLD) and Autosomal Dominant Polycystic Kidney Disease (ADPKD). The molecular principles in carcinogenesis indicate that there is an accumulation of multiple (somatic) mutations. This concept assumes that presence of a germline mutation (‘first hit’) in an inherited disorder requires a ‘second hit’ at the somatic level for cyst development to occur. The second hit is the rate-limiting step and results in somatic inactivation of the normal allele. Studies have identified secondary, somatic hits in human liver cyst tissues in PCLD and ADPKD. Inactivation of both copies in PLD is demonstrated through somatic mutations or loss of heterozygosity (LOH). The frequency of somatic mutations varies between genes and genomic disorders. Genetic studies detected LOH in 9% and somatic mutations in 8-29% in ADPKD derived hepatic cysts. In PCLD, almost ~80% of hepatic cysts from PRKCSH carriers had completely lost the PRKCSH gene. There is important clinical heterogeneity among PLD patients. Differences in phenotypical expression may be explained by age, gender and environment, but also modifier genes or inactivating somatic events may play key roles. This review will give an overview of the data gained from genetic studies in liver cyst tissues from PCLD and ADPKD patients in relation to the clinical manifestations.