Can a signature molecular-profile define disparate survival in BRAF-positive Gliosarcoma and identify novel targets for therapeutic intervention?

Abstract

Gliosarcoma (GS) has a low incidence but is aggressively invasive, with poor-survival. Even though GS is recognized as a different subgroup from glioblastoma (GB), there is no molecular panel available to define its clinical outcome. The objective was to identify the molecular imprint of GS in terms of expression of human telomerase reverse transcriptase (hTERT), high mobility group A1 (HMGA-1), kinesin superfamily protein-14 (KIF-14), epidermal growth factor receptor (EGFR) markers with reference to disparate prognosis and identify plausible targets for intervention. We retrieved 9-GS samples from a cohort of 57-GB patients during a 36 months study period and compared them with 10 molecularly typed GB-samples and 15 controls. Conventional-immunohistochemistry (IHC) was used for histopathology of GS and immunofluorescence-IHC was performed for quantification of identified marker-panel. Statistical tools for non-parametric data were used for inferring results. GS was confirmed by reticulin-staining and positivity for glial fibrillary acidic protein, Vimentin, smooth muscle actin. Immune-reactivity for BRAF-V600Ewas present in both glial and sarcomatous cells and negative expression of isocitrate dehydrogenase, ATRX, TP53.Comparison between GS, GB, and control tissues showed that the expression of markers reached significance (P < 0.0001), without the influence of confounders. Significant correlation of EGFR was found with hTERT (r = 0.77), HMGA-1 (r = 0.72), KIF-14 (r = 0.82) suggesting that their combined analysis can define prognosis. To establish the diagnostic accuracy (threshold ≥80% specificity), AUC for EGFR was 0.78 (>3.95), KIF-14 0.97 (>7.45), hTERT 0.63 (>23.86), and HMGA-1 0.53 (>15.45). This is the first evidence-based investigation presenting differential expression of proliferation and stemness markers hTERT, HMGA-1, KIF-14 in-correlation with EGFR, indicating a plausible-association between survival and disease-progression in individual GS-cases. It can serve as a model for further studies in this glioma-subgroup and the designing of a target panel for personalized treatment.