Epigenetic PTEN Silencing in Malignant Melanomas without PTEN Mutation

摘要: A tumor suppressor gene at 10q 23.3, designated PTEN, encoding a dual specificity phosphatase with lipid and protein activity, has been shown to play an important role in the pathogenesis of variety human cancers. Germline mutations PTEN cause Cowden syndrome (CS), which is characterized by multiple hamartomas high risk breast thyroid Frequent loss heterozygosity found both early advanced-stage sporadic melanomas; however, or deletions are detected mainly melanoma cell lines. In this study, we examined expression 34 unselected melanomas (4 primary melanomas, 30 metastases) using immunohistochemistry correlated results structural studies gene. Immunostaining samples revealed no 5 (15%) low 17 (50%), whereas rest tumors (35%) had levels expression. Hemizygous deletion was 32% but neither intragenic mutation nor biallelic any samples. Of showing expression, 4 PTEN. 13 having weak immunoreactivity informative results, 6 evidence hemizygous allelic while remaining 7 intact These strongly support as major on involved tumorigenesis suggest epigenetic mechanism functional inactivation not previously observed other cancers where might be involved.