Expression of Epidermal Growth Factor Receptor (EGF-R) and Erb-B2 (HER 2/NEU) in Glioblastoma (GEM): Prognosttc Relevance
Archival material from 17 untreated primary adult GEMs were analyzed retrospectively using immunocytochemistry for the expression of EGF-R and ErbB2. Patients were divided into long term survivors (LTS) (N=10, median survival >4 yrs) and short term survivors (STS) (N=7, median survival 61 wks, mean ± SEM time to recurrence 22 ± 3 wks). There were no biologically significant differences between the groups in terms of age, post-operative Karnofsky status, or post-operative treatment (standard cranial radiation and chemotherapy). 6/7 of the STS had >90% of tumor resected compared with 6/10 of the LTS. All STS underwent debulking reoperation at suspected recurrence, confirming tumor regrowth as the cause of death in all STS. Histologically diagnostic paraffin sections were stained with monoclonal antibodies to EGF-R and ErbB2. Tumor staining was scored as 1 to 3: scant/ negative; ≦25% but <75% positive, or ≦75% positive. Scores of 2 and 3 were considered positve (+). Each tumor section was scored for positivity by 3 independent observers, blinded as to patient’s name and history. There was general concordance between all three observers. All LTS were EGF-R negative/ scant and 7/10 were ErbB2 negative/scant. 4/7 STS were EGF-R+, 5/7 were ErbB2+, and 4/7 were positive for both proteins. Recurrrent tumors in STS had increased expression of EGF-R in 4/7 of cases and of ErbB2 in 7/7 cases over the pretreatment baseline. EGF-R negativity correlated best with long term survival, while ErbB2 positivity better predicted short term survival. Increased growth factor expression appears to be associated with aggressive clinical behavior and treatment resistance.
KeywordsEpidermal Growth Factor Receptor Glial Fibrillary Acidic Protein Malignant Glioma Epidermal Growth Factor Receptor Expression Short Term Survivor
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