EGFR and central nervous system cancer: When a copy number of ≥4 of the indicated genes was considered as CNG (or gene amplification), we found that EGFR CNG in 62/127 (48.8%) gliomas, HER2 in 44/127 (34.6%) gliomas, HER3 in 47/127 (37.0%) gliomas, and HER4 in 50/127 (39.4%) gliomas, whereas none was found in control subjects (Table 1).