title: Topoisomerase I protein expression in primary colorectal cancer and recurrences after 5-FU-based adjuvant chemotherapy.
abstract: OBJECTIVE
  Our aim was to investigate whether chemotherapy with 5-FU induces an alteration in the levels of topoisomerase I (topo I) in colorectal neoplastic tissues
  
  
  METHODS
  Twenty-five colorectal cancer patients were included in our study; these had undergone surgical resection of the primary tumor, received post-operatively 5-FU-based adjuvant chemotherapy and then suffered from recurrences. In a standard three-step immunohistochemical procedure, a monoclonal antibody to topo I was applied in both specimens from each patient (one from the primary location and a second one from the recurrence). Statistical analysis was subsequently performed.
  
  
  RESULTS
  Malignant cells from the recurrences displayed a statistical significant increase, concerning the levels of topoisomerase I, by comparison with the primary tumors (P=0.01). The increase in topo I levels did not demonstrate significant correlations with Duke's stage (Fisher's Exact Test P value=0.496), differentiation grade (P value=0.661), localization (P value=0.072), patient sex (P value=0.434), nor with relapse free interval (P value=0.493). There was a statistically significant relationship between the age of patients and increase in topo I levels (P=0.011).
  
  
  CONCLUSIONS
  Topo I expression may be part of the malignant cells' phenotype in recurrent colorectal carcinomas, suggesting a potential role for Topo I in the acquisition of a metastatic phenotype. The increase of topo I immunohistochemical status is likely to be attributed to 5-FU and given the fact that high levels of topo I correlate with sensitivity to camptothecin, advanced colorectal cancer patients seem to benefit from topo I targeted anticancer drug therapy.
authors.affiliation: Medical Oncology Unit, Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Gouveris
authors.forename: A C
authors.initials: AC
authors.lastname: Lazaris
authors.forename: T G
authors.initials: TG
authors.lastname: Papathomas
authors.forename: A
authors.initials: A
authors.lastname: Nonni
authors.forename: V
authors.initials: V
authors.lastname: Kyriakou
authors.forename: J
authors.initials: J
authors.lastname: Delladetsima
authors.forename: E S
authors.initials: ES
authors.lastname: Patsouris
authors.forename: N
authors.initials: N
authors.lastname: Tsavaris
mesh_terms: D000367:Age Factors; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000201:enzymology*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012737:Sex Factors
chemical_list: D004264:DNA Topoisomerases, Type I; D005472:Fluorouracil