title: Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy.
abstract: BACKGROUND
  Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours.
  
  
  METHODS
  The chemosensitivity of a series of 31 ovarian tumours, all previously treated with platinum-based chemotherapy, was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA) and correlated with resistance gene expression measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from formalin-fixed paraffin-embedded tissue. The results were standardised against a housekeeping gene (PBGD), and assessed by multiple linear regression.
  
  
  RESULTS
  Predictive multiple linear regression models were derived for four single agents (cisplatin, gemcitabine, topotecan, and treosulfan), and for the combinations of cisplatin+gemcitabine and treosulfan+gemcitabine. Particularly strong correlations were obtained for cisplatin, gemcitabine, topotecan, and treosulfan+gemcitabine. No individual gene expression showed direct correlation with activity in the ATP-TCA. Genes involved in DNA repair and apoptosis were strongly represented, with some drug pumps also involved.
  
  
  CONCLUSIONS
  The chemosensitivity of ovarian cancer to drugs is related to the expression of genes involved in sensitivity and resistance mechanisms.
authors.affiliation: Translational Oncology Research Centre, Queen Alexandra Hospital, Portsmouth PO6 3LY, UK.
authors.forename: S
authors.initials: S
authors.lastname: Glaysher
authors.forename: F G
authors.initials: FG
authors.lastname: Gabriel
authors.forename: P
authors.initials: P
authors.lastname: Johnson
authors.forename: M
authors.initials: M
authors.lastname: Polak
authors.forename: L A
authors.initials: LA
authors.lastname: Knight
authors.forename: K
authors.initials: K
authors.lastname: Parker
authors.forename: M
authors.initials: M
authors.lastname: Poole
authors.forename: A
authors.initials: A
authors.lastname: Narayanan
authors.forename: I A
authors.initials: IA
authors.lastname: Cree
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002066:Busulfan / Q000008:administration & dosage / Q000031:analogs & derivatives; D002945:Cisplatin / Q000008:administration & dosage*; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000188:drug therapy*; D019772:Topotecan / Q000008:administration & dosage; D000093542:Gemcitabine
chemical_list: D003841:Deoxycytidine; D019772:Topotecan; C018404:treosulfan; D002066:Busulfan; D002945:Cisplatin; D000093542:Gemcitabine