Article
Study of PTEN methylation in 69 cases of cerebral cavernous malformations (CCMs). Possible impact on familial cases
PTEN-Methylierung in 69 Fällen von zerebralen Kavernomen. Möglicher Einfluss auf familiäre Fälle
Search Medline for
Authors
Published: | April 11, 2007 |
---|
Outline
Text
Objective: We and others have demonstrated that CCM is a dynamically developing disease involving neoangiogenesis. Our rescent study has revealed a significant loss of PTEN in the cerebral vessels of CCM and furthermore a crucial role of PTEN in angiogenesis. Frequent PTEN deficiency due to promoter hypermethylation has been reported in various cancers. It is highly interesting to explore whether PTEN methylation occurs in CCM patients and whether this epigenic mutation accounts for PTEN loss in CCM patients.
Methods: To study PTEN methylation, genomic DNA was extracted from 69 CCM brain tissues and 4 blood cell samples from familial CCMs (f-CCMs). DNA was modified by sodium bisulfite followed by methylation specific PCR (MSP). A positive control was prepared using the genomic DNA from healthy human blood that was treated with SssI methylase. To find out the correlation of PTEN expression and methylation, immunostaining of PTEN was performed.
Results: MSP revealed PTEN methylation positive with 10 among 69 brain tissues of CCMs (14.5%). Interestingly, all 4 f-CCMs showed PTEN methylation positive. The incidence of PTEN methylation in f-CCMs (100%) is significantly higher than the sporadic one (9.2%) (p<0.001). Of note, only 1 among 4 cases of f-CCMs showed PTEN methylation positive both in blood cells and in surgical tissues, whereas other 3 cases showed negative in blood cell sample indicating a tissue-specific PTEN methylation in these cases. Immunostaining demonstrated a significant higher PTEN loss in PTEN methylation positive cases (67%) in comparison to that in methylation negative CCMs (29%) (p<0.001).
Conclusions: The present study reports for the first time that PTEN methylation is present in the lesioned brain tissue of CCM patients, particularly in f-CCMs, suggesting a possible novel diagnosis parameter among others for f-CCMs.