Four invasive margin proteins were chosen and excised from 2D-PAGE gels, prior to MS/MS analysis (Fig. 6E), and these were identified as cytoplasmic proteins α-trypsin, actin, apolipoprotein A1 and transthyretin which may putatively be associated with a GBM infiltrative phenotype (Table 3). This evidence concerns the gene APOA1 and glioblastoma.