Table 1. Studies evaluating prognostic and/or predictive role of EGFRvIII in GBM.

Author, year	No. GBM cases	Treatment	Assay Technique	Prognostic/predictive value	Proposed molecular mechanism
Heimberger et al, 2005 [21]	196	Stupp	IHC	↓ (for long survivors)	cell proliferation, ependymal involvement
Liu et al, 2005 [22]	160	Stupp	PCR	none	NA
Heimberger et al, 2005 [23]	54	Stupp	IHC	none	NA
Mellinghoff et al, 2005 [16]	50	erlotinib / gefitinib (recurrence)	IHC, PCR, western blotting	↑ (erlotinib)	EGFRvIII/PTEN co-expression
Pelloski et al, 2007 [24]	509	Stupp	IHC	↓ (OS)	none
Viana-Pereira et al, 2008 [25]	27	Stupp	IHC	none	NA
Brown et al, 2008 [26]	81	Stupp + erlotinib	IHC	none	NA
Van den Bent et al, 2009 [27]	49	erlotinib vs TMZ/BCNU	IHC	↓ (erlotinib)	none
Thiessen et al, 2009 [28]	16	lapatinib (recurrence)	PCR	none	NA
Reardon et al, 2009 [29]	20	erlotinib + sirolimus (recurrence)	IHC	none	NA
Uhm et al, 2011 [30]	96	RT+ gefitinib	IHC	none	NA
Montano et al, 2011 [15]	73	Stupp	PCR	↑ (OS)	increased effectiveness of TMZ in EGFRvIII-positive cells due to pathway addiction
Lv et al, 2012 [31]	35	cetuximab	IHC, PCR	↓ (OS, PFS)	none
Bienkowski et al, 2013 [32]	83	RT or RT+CT	PCR, FISH	↑ (OS)	none
D’Alessandris et al, 2013 [8]	10	bev + erlotinib (recurrence)	PCR	↑ (erlotinib)	tailored therapy
Weller et al, 2014 [33]	184	Stupp	IHC, PCR, MLPA	none	possible false-negative testings
Gallego et al, 2014 [34]	13 recurrent	erlotinib	IHC	none	genetic heterogeneity of GBM

^↓negative prognostic/predictive value;

^↑positive prognostic/predictive value.

bev, bevacizumab; BCNU, bis-chloroethylnitrosourea; CT, chemotherapy; EGFRvIII, epidermal growth factor receptor variant III; FISH, fluorescence in situ hybridization; IHC, immunohistochemistry; MLPA, multiplex ligation-dependent probe amplification; NA, not available; OS, overall survival; PCR, polymerase chain reaction; PTEN, phosphatase and tensin homolog; PFS, progression-free survival; RT, radiotherapy; TMZ, temozolomide.