title: Potential predictive markers of chemotherapy resistance in stage III ovarian serous carcinomas.
abstract: BACKGROUND
  Chemotherapy resistance remains a major obstacle in the treatment of women with ovarian cancer. Establishing predictive markers of chemoresponse would help to individualize therapy and improve survival of ovarian cancer patients. Chemotherapy resistance in ovarian cancer has been studied thoroughly and several non-overlapping single genes, gene profiles and copy number alterations have been suggested as potential markers. The objective of this study was to explore genetic alterations behind chemotherapy resistance in ovarian cancer with the ultimate aim to find potential predictive markers.
  
  
  METHODS
  To create the best opportunities for identifying genetic alterations of importance for resistance, we selected a homogenous tumor material concerning histology, stage and chemotherapy. Using high-resolution whole genome array comparative genomic hybridization (CGH), we analyzed the tumor genomes of 40 fresh-frozen stage III ovarian serous carcinomas, all uniformly treated with combination therapy paclitaxel/carboplatin. Fisher's exact test was used to identify significant differences. Subsequently, we examined four genes in the significant regions (EVI1, MDS1, SH3GL2, SH3KBP1) plus the ABCB1 gene with quantitative real-time polymerase chain reaction (QPCR) to evaluate the impact of DNA alterations on the transcriptional level.
  
  
  RESULTS
  We identified gain in 3q26.2, and losses in 6q11.2-12, 9p22.3, 9p22.2-22.1, 9p22.1-21.3, Xp22.2-22.12, Xp22.11-11.3, and Xp11.23-11.1 to be significantly associated with chemotherapy resistance. In the gene expression analysis, EVI1 expression differed between samples with gain versus without gain, exhibiting higher expression in the gain group.
  
  
  CONCLUSIONS
  In conclusion, we detected specific genetic alterations associated with resistance, of which some might be potential predictive markers of chemotherapy resistance in advanced ovarian serous carcinomas. Thus, further studies are required to validate these findings in an independent ovarian tumor series.
authors.affiliation: Department of Oncology, Institute of Clinical Sciences, University of Gothenburg, Sweden. lovisa.osterberg@gu.se
authors.forename: Lovisa
authors.initials: L
authors.lastname: Osterberg
authors.forename: Kristina
authors.initials: K
authors.lastname: Levan
authors.forename: Karolina
authors.initials: K
authors.lastname: Partheen
authors.forename: Ulla
authors.initials: U
authors.lastname: Delle
authors.forename: Björn
authors.initials: B
authors.lastname: Olsson
authors.forename: Karin
authors.initials: K
authors.lastname: Sundfeldt
authors.forename: György
authors.initials: G
authors.lastname: Horvath
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics*; D016190:Carboplatin / Q000627:therapeutic use; D018284:Cystadenocarcinoma, Serous / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D019008:Drug Resistance, Neoplasm; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D017239:Paclitaxel / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D016190:Carboplatin; D017239:Paclitaxel