In order to test this hypothesis further, 101 myxopapillary, conventional, and anaplastic ependymomas (51 spinal and 50 intracranial tumors) were tested for RB and p16 deletions using fluorescence in situ hybridization.
Only p16 (INK4A )and TIMP3 were methylated consistently in medulloblastomas (p16 (INK4A ) 14%, TIMP3 11%) and p16 (INK4A) also in anaplastic ependymomas (1/4 tumors).Methylation ranged from 1-5%.