Prognostic Significance of Epidermal Growth Factor Receptor in Patients of Glioblastoma Multiforme

Glioblastoma Multiforme (GBM) is the most aggressive glial tumour with hallmark characteristics of rampant proliferation of glial cells along with high pleomorphism, necrosis, endothelial proliferation and high MIB-1 labeling index (cell proliferation marker). These tumours are managed by surgery followed by Radiotherapy (RT), Chemotherapy (CT) and adjuvant CT Temozolomide (TMZ).

To evaluate Epidermal Growth Factor Receptor (EGFR) protein expression in GBM patients.

The study comprised of 52 cases of GBM diagnosed by histomorphology from biopsy specimens. Ancillary techniques like Immunohistochemistry (IHC) for Glial Fibrillary Acidic Protein (GFAP), cell proliferation marker (MIB-1 labeling index, P53 expressions) were done in all cases. EGFR protein expression was assessed by IHC as the percentage of positive tumour cells in hot spots (10 high power fields). Response to therapy was assessed at three months post therapy by using World Health Organization (WHO) Response Evaluation Criteria In Solid Tumours (RECIST) guideline. Statistical analysis was performed by using IBM-Statistical Package for Social Sciences (SPSS) software, version 20. The p-value of ≤ 0.05 was considered significant. The mean survival of the patients was calculated using unpaired t-test and ANOVA (analysis of variance) test.

Out of 52 cases, thirty cases was EGFR positive and 22 cases were EGFR negative. Response to therapy was evident in 33 (63.5%) cases and 19 cases (36.5%) were non responders. The responders with EGFR negative were 86.4% and EGFR positive were 46.7% with a p-value of 0.003. The mean survival among EGFR positive and negative GBM were 315.73±257.54 and 657.91±305.88 days respectively with a significant p-value of 0.001.

EGFR negative patients respond better to therapy along with longer duration of survival as compared to EGFR positive patient.