Fig. 1

Development and characterisation by gene expression profiling of cytotoxic drug resistant gastroesophageal cancer cell lines. a Drug resistant cell lines used in this study (see also Additional file 1). b Principle component analysis of drug resistant cell lines using 16939 genes expressed in at least 1 cell line (threshold of expression ≥ 20th percentile) with 3 independent replicates per cell line from three different passages using Affymetrix Exon 1.0ST microarrays (see also Additional File 1: Additional information 2). c Only 3 pathways, namely the lysosome, sphingolipid metabolism and p53 signalling were identified as over-represented in gene set enrichment analysis of genes significantly differentially expressed for all 3 cytotoxic drugs compared to sensitive parental lines and in each case they were also identified in at least 2 cell lineages (DAVID v6.7 for biological pathway mapping and gene set enrichment analysis (EASE score, modified Fisher exact p < 0.05 [16]), Paired t-test with Benjamini and Hochberg correction for multiple testing (corrected P <0.05) to derive the differentially expressed gene set, green = over represented red = not over-represented. See also Additional file 1: Additional information 7