HB-EGF mRNA expression is two- to five-fold higher in human glioblastomas than in normal brain tissue [37], and the HB-EGF receptors—EGFR homodimer and EGFR/ErbB2 heterodimer—are both commonly amplified in glioblastomas [29, 38, 39]. This evidence concerns the gene ERBB2 and glioblastoma.