ABSTRACT
<p><b>OBJECTIVE</b>To investigate the methylation of p16(INK4a) and RB gene, and the expression of p16(INK4a) in meningiomas.</p><p><b>METHODS</b>Methylation-specific polymerase chain reaction (MSP) was used to detect the methylation of p16(INK4a) and RB in 50 cases of meningiomas, and immunostaining was performed to analyze the protein expression of p16(INK4a) in 25 of those cases.</p><p><b>RESULTS</b>No methylation was found in the benign meningiomas, whereas methylation of p16(INK4a)or RB occurred in 6(37.5%) cases of grade II tumors and 4(28.6%) cases of grade III tumors, and among these cases, an atypical meningioma showed methylation of both genes. Thirteen cases showed p16(INK4a) positive expression, but none of them was methylated.</p><p><b>CONCLUSION</b>The methylation of p16(INK4a) or RB is related with the tumorigenesis and progression of atypical and anaplastic meningiomas, and a probable mechanism is that methylation causes the loss of expression and leads to dysfuncation of the p16(INK4a)/cyclin D1/CDK4/RB pathway.</p>