title: Prognostic markers in early-stage colorectal cancer: significance of TYMS mRNA expression.
abstract: BACKGROUND
  Several studies have recently indicated the prognostic or predictive role of several biomarkers in colorectal cancer. We sought to investigate the prognostic value of prostaglandin synthase 2 (PTGS2), cyclooxygenase 2 (COX2), thymidylate synthetase (TYMS), thymidine phosphorylase (TYMP), dihydropyrimidine dehydrogenase (DPYD) and topoisomerase I (TOPO1) in colorectal cancer patients treated with 5-FU-based regimens, such as De Gramont and FOLFOX in the adjuvant setting.
  
  
  METHODS
  In total, 96 formalin-fixed paraffin-embedded and 30 fresh-frozen tumor tissue samples were evaluated using immunohistochemistry, quantitative reverse transcription-polymerase chain reaction and microarray gene expression profiling, respectively.
  
  
  RESULTS
  The majority of tumors exhibited protein overexpression of COX2 (69%), TYMS (75%) and TOPO1 (75%). There was a significant association of TYMP protein expression with T classification, gender and stage (p=0.040, p=0.041 and p=0.011, respectively). TOPO1 protein expression was correlated with TOPO1 mRNA expression and was positively associated with stage (p=0.002) and lymph node infiltration (p=0.004). In univariate analysis, patients with high TYMS mRNA expression were shown to have a significantly lower risk for progression and death (Wald's p=0.030 and p=0.015, respectively). However, in multivariate analysis, only a trend for decreased risk for death was shown in patients with high TYMS mRNA expression (Wald's p=0.083), while patients with high PTGS2 mRNA expression had a trend for lower risk for progression (p=0.064). Using supervised hierarchical clustering, based on the expression in fresh-frozen tumor tissue of PTGS2, TYMS, TYMP and DPYD, our 30 patients were separated into two clusters. One of the clusters was enriched with patients with infiltrated lymph nodes (p<0.05), suggesting that these genes might have an impact on the tumor's ability to metastasize.
  
  
  CONCLUSIONS
  These findings indicate a possible prognostic role of TYMS mRNA expression and highlight a cluster of genes associated with nodal metastases that warrant further investigation in a larger cohort of patients with colorectal cancer treated with 5-FU-based adjuvant chemotherapy.
authors.affiliation: Fourth Department of Internal Medicine, Attikon University Hospital, Athens, Greece akoumari@yahoo.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Koumarianou
authors.affiliation: First Propaedeutic Department of Surgery, AHEPA Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Tzeveleki
authors.affiliation: First Propaedeutic Department of Surgery, AHEPA Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Dimosthenis
authors.initials: D
authors.lastname: Mekras
authors.affiliation: Section of Biostatistics, Hellenic Cooperative Oncology Group, Data Office, Athens, Greece.
authors.forename: Anastasia G
authors.initials: AG
authors.lastname: Eleftheraki
authors.affiliation: Laboratory of Molecular Oncology, Hellenic Foundation for Cancer Research, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Mattheos
authors.initials: M
authors.lastname: Bobos
authors.affiliation: STRATIFYER Molecular Pathology GmbH, Cologne, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Wirtz
authors.affiliation: Department of Medical Oncology, Papageorgiou Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Elena
authors.initials: E
authors.lastname: Fountzilas
authors.affiliation: Department of Pathology, Metaxas Cancer Hospital, Piraeus, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Valavanis
authors.affiliation: Department of Medical Oncology, Papageorgiou Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Xanthakis
authors.affiliation: Department of Medical Oncology, Papageorgiou Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece Translational Research Section, Hellenic Cooperative Oncology Group, Data Office, Athens, Greece.
authors.forename: Konstantine T
authors.initials: KT
authors.lastname: Kalogeras
authors.affiliation: First Propaedeutic Department of Surgery, AHEPA Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Basdanis
authors.affiliation: Department of Medical Oncology, Ioannina University Hospital, Ioannina, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Pentheroudakis
authors.affiliation: Laboratory of Molecular Oncology, Hellenic Foundation for Cancer Research, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece Department of Pathology, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Kotoula
authors.affiliation: Laboratory of Molecular Oncology, Hellenic Foundation for Cancer Research, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece Department of Medical Oncology, Papageorgiou Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Fountzilas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D013940:Thymidylate Synthase / Q000235:genetics; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D013940:Thymidylate Synthase
keywords: 5-FU-based adjuvant chemotherapy; COX2; DPYD; PTGS2; TOPO1; TYMP; TYMS; hierarchical clustering; stage II colorectal cancer; stage III colorectal cancer