title: Expression profiling of stem cell-related genes in neoadjuvant-treated gastric cancer: a NOTCH2, GSK3B and β-catenin gene signature predicts survival.
abstract: Cancer stem cell (CSC) based gene expression signatures are associated with prognosis in various tumour types and CSCs are suggested to be particularly drug resistant. The aim of our study was first, to determine the prognostic significance of CSC-related gene expression in residual tumour cells of neoadjuvant-treated gastric cancer (GC) patients. Second, we wished to examine, whether expression alterations between pre- and post-therapeutic tumour samples exist, consistent with an enrichment of drug resistant tumour cells. The expression of 44 genes was analysed in 63 formalin-fixed, paraffin embedded tumour specimens with partial tumour regression (10-50% residual tumour) after neoadjuvant chemotherapy by quantitative real time PCR low-density arrays. A signature of combined GSK3B(high), β-catenin (CTNNB1)(high) and NOTCH2(low) expression was strongly correlated with better patient survival (p<0.001). A prognostic relevance of these genes was also found analysing publically available gene expression data. The expression of 9 genes was compared between pre-therapeutic biopsies and post-therapeutic resected specimens. A significant post-therapeutic increase in NOTCH2, LGR5 and POU5F1 expression was found in tumours with different tumour regression grades. No significant alterations were observed for GSK3B and CTNNB1. Immunohistochemical analysis demonstrated a chemotherapy-associated increase in the intensity of NOTCH2 staining, but not in the percentage of NOTCH2. Taken together, the GSK3B, CTNNB1 and NOTCH2 expression signature is a novel, promising prognostic parameter for GC. The results of the differential expression analysis indicate a prominent role for NOTCH2 and chemotherapy resistance in GC, which seems to be related to an effect of the drugs on NOTCH2 expression rather than to an enrichment of NOTCH2 expressing tumour cells.
authors.affiliation: Institute of Pathology, Technische Universität München, München, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Bauer
authors.forename: Rupert
authors.initials: R
authors.lastname: Langer
authors.forename: Karen
authors.initials: K
authors.lastname: Becker
authors.forename: Alexander
authors.initials: A
authors.lastname: Hapfelmeier
authors.forename: Katja
authors.initials: K
authors.lastname: Ott
authors.forename: Alexander
authors.initials: A
authors.lastname: Novotny
authors.forename: Heinz
authors.initials: H
authors.lastname: Höfler
authors.forename: Gisela
authors.initials: G
authors.lastname: Keller
mesh_terms: D017024:Chemotherapy, Adjuvant; D005260:Female; D020869:Gene Expression Profiling; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D051883:Receptor, Notch2 / Q000235:genetics*; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D015996:Survival Rate; D051176:beta Catenin / Q000235:genetics*
chemical_list: C497764:NOTCH2 protein, human; D051883:Receptor, Notch2; D051176:beta Catenin; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3