ERBB2, ERBB4, and human telomerase reverse transcriptase (TERT) gene expression promote tumor cell proliferation, contributing to aggressive tumor behavior.[8][9][10] High expression of epidermal growth factor receptor (EGFR) correlates with unfavorable outcome.[9] Over-expression of kinetochore proteins and down-regulation of metallothioneins are associated with recurrence in ependymomas.[11] KIT receptor tyrosine kinase and phospho-KIT were found to be present in pediatric ependymomas and may be involved in angiogenesis associated with those tumors.[12]