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PDF file - 82K, GBM Patient Data (S1); EGFRvIII and CD133 expression in GBM Neurospheres or Normal Brain (NB) derived Neurospheres (S2); Percentage of co-localization of EGFRvIII+ with Markers of Differentiation and Stem/Progenitor Cells (S3).

PDF file - 3725K, Gating Tree for Fluorescence Activated Cell Sorting (FACS) Analysis (S1); Vessel Staining of EGFRvIII in GBM Xenografts (S2); Characterization and Affinity Analysis of the Recombinant Antibodies (S3); Antibody Dependent Cellular Cytotoxicity Induced by BsAb (S4); Limiting Dilution Analysis of Unsorted Tumor Spheres Before and After BsAb Induced ADCC (S5).

The relationship between mutated proteins and the cancer stem-cell population is unclear. Glioblastoma tumors frequently express EGFRvIII, an EGF receptor (EGFR) variant that arises via gene rearrangement and amplification. However, expression of EGFRvIII is restricted despite the prevalence of the alteration. Here, we show that EGFRvIII is highly coexpressed with CD133 and that EGFRvIII+/CD133+ defines the population of cancer stem cells (CSC) with the highest degree of self-renewal and tumor-initiating ability. EGFRvIII+ cells are associated with other stem/progenitor markers, whereas markers of differentiation are found in EGFRvIII− cells. EGFRvIII expression is lost in standard cell culture, but its expression is maintained in tumor sphere culture, and cultured cells also retain the EGFRvIII+/CD133+ coexpression, self-renewal, and tumor initiating abilities. Elimination of the EGFRvIII+/CD133+ population using a bispecific antibody reduced tumorigenicity of implanted tumor cells better than any reagent directed against a single epitope. This work demonstrates that a mutated oncogene can have CSC-specific expression and be used to specifically target this population. Cancer Res; 74(4); 1238–49. ©2013 AACR.

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EGFRvIII is a tumor-specific variant of the epidermal growth factor receptor (EGFR). Although EGFRvIII is most commonly found in glioblastoma, its expression in other tumor types remains controversial. In this study, we investigated EGFRvIII expression and amplification in primary breast carcinoma. Our analyses confirmed the presence of EGFRvIII, but in the absence of amplification or rearrangement of the EGFR locus. Nested reverse transcriptase PCR and flow cytometry were used to detect a higher percentage of positive cases. EGFRvIII-positive cells showed increased expression of genes associated with self-renewal and epithelial–mesenchymal transition along with a higher percentage of stem-like cells. EGFRvIII also increased in vitro sphere formation and in vivo tumor formation. Mechanistically, EGFRvIII mediated its effects through the Wnt/β-catenin pathway, leading to increased β-catenin target gene expression. Inhibition of this pathway reversed the observed effects on cancer stem cell (CSC) phenotypes. Together, our findings show that EGFRvIII is expressed in primary breast tumors and contributes to CSC phenotypes in breast cancer cell lines through the Wnt pathway. These data suggest a novel function for EGFRvIII in breast tumorigenesis. Cancer Res; 72(10); 2657–71. ©2012 AACR.

Background Worldwide, socioeconomic differences in health and use of healthcare resources have been reported, even in countries providing universal healthcare coverage. However, it is unclear how large these socioeconomic differences are for different types of care and to what extent health status plays a role. Therefore, our aim was to examine to what extent healthcare expenditure and utilization differ according to educational level and income, and whether these differences can be explained by health inequalities. Methods Data from 18,936 participants aged 25–79 years of the Dutch Health Interview Survey were linked at the individual level to nationwide claims data that included healthcare expenditure covered in 2017. For healthcare utilization, participants reported use of different types of healthcare in the past 12 months. The association of education/income with healthcare expenditure/utilization was studied separately for different types of healthcare such as GP and hospital care. Subsequently, analyses were adjusted for general health, physical limitations, and mental health. Results For most types of healthcare, participants with lower educational and income levels had higher healthcare expenditure and used more healthcare compared to participants with the highest educational and income levels. Total healthcare expenditure was approximately between 50 and 150 % higher (depending on age group) among people in the lowest educational and income levels. These differences generally disappeared or decreased after including health covariates in the analyses. After adjustment for health, socioeconomic differences in total healthcare expenditure were reduced by 74–91 %. Conclusions In this study among Dutch adults, lower socioeconomic status was associated with increased healthcare expenditure and utilization. These socioeconomic differences largely disappeared after taking into account health status, which implies that, within the universal Dutch healthcare system, resources are being spent where they are most needed. Improving health among lower socioeconomic groups may contribute to decreasing health inequalities and healthcare spending.