Methylated genes as new cancer biomarkersBrünner, Nils; Duffy, M.J; Napieralski, R.; Martens, J.W.M. ; Span, P.N. ; Spyratos, F.; Sweep, F.C.G.J.; Foekens, J.A. ; Schmitt, M. GSTP1 for aiding the early diagnosis of prostate cancer, methylated PITX2 for predicting outcome in lymph node-negative breast cancer patients and methylated MGMT in predicting benefit from alkylating agents in patients with glioblastomas. However, prior to clinical utilisation, these findings require validation in prospective clinical studies. Furthermore, assays for measuring gene methylation need to be standardised, simplified and evaluated in external quality assurance programmes. It is concluded that methylated genes have the potential to provide a new generation of cancer biomarkers.

BackgroundNon-small cell lung cancer (NSCLC), a leading cause of cancer deaths, represents a heterogeneous group of neoplasms, mostly comprising squamous cell carcinoma (SCC), adenocarcinoma (AC) and large-cell carcinoma (LCC). The objectives of this study were to utilize integrated genomic data including copy-number alteration, mRNA, microRNA expression and candidate-gene full sequencing data to characterize the molecular distinctions between AC and SCC.MethodsComparative genomic hybridization followed by mutational analysis, gene expression and miRNA microarray profiling were performed on 123 paired tumor and non-tumor tissue samples from patients with NSCLC.ResultsAt DNA, mRNA and miRNA levels we could identify molecular markers that discriminated significantly between the various histopathological entities of NSCLC. We identified 34 genomic clusters using aCGH data; several genes exhibited a different profile of aberrations between AC and SCC, including PIK3CA, SOX2, THPO, TP63, PDGFB genes. Gene expression profiling analysis identified SPP1, CTHRC1and GREM1 as potential biomarkers for early diagnosis of the cancer, and SPINK1 and BMP7 to distinguish between AC and SCC in small biopsies or in blood samples. Using integrated genomics approach we found in recurrently altered regions a list of three potential driver genes, MRPS22, NDRG1 and RNF7, which were consistently over-expressed in amplified regions, had wide-spread correlation with an average of ~800 genes throughout the genome and highly associated with histological types. Using a network enrichment analysis, the targets of these potential drivers were seen to be involved in DNA replication, cell cycle, mismatch repair, p53 signalling pathway and other lung cancer related signalling pathways, and many immunological pathways. Furthermore, we also identified one potential driver miRNA hsa-miR-944.ConclusionsIntegrated molecular characterization of AC and SCC helped identify clinically relevant markers and potential drivers, which are recurrent and stable changes at DNA level that have functional implications at RNA level and have strong association with histological subtypes.

Purpose: We evaluated the expression of seven therapy-related genes to predict the clinical outcome of advanced gastric cancer patients treated with a neoadjuvant chemotherapeutic protocol. Experimental Design: Pretherapeutic, formalin-fixed, and paraffin-embedded biopsies of 61 patients, who received a 5-fluorouracil (5-FU)^and cisplatin-based chemotherapy were studied. The expressions of the 5-FU^related genes TS, DPD, and TP and of the cisplatin-related genes ERCC1, ERCC4, KU80, and GADD45A were analyzed by quantitative real-time PCR.The expression levels of single genes and of various combinations were tested for an association with response and overall survival. Results: High DPD levels were more frequently found in nonresponding patients and were associated with worse survival. GADD45A and TP levels showed weak associations with response, but GADD45A expression correlated with survival. There was no association with response for TS expression, but tumors with a high TS level were associated with worse survival. The combination of GADD45A and TP revealed the strongest predictive effect. High expression values of TP and/or GADD45A were exclusively found in nonresponding patients (P = 0.002) and were associated with a significantly poorer survival (P = 0.04). Conclusions: Combined gene expression levels ofTP and GADD45A represent a new variable to predict the clinical outcome after neoadjuvant chemotherapy in gastric cancer. The association of DPD expression with response and survival underlines a predominant role of DPD to predict 5-FU sensitivity.The association ofTS expression levels with survival but not with response suggests an importance of this gene for tumor progression.