title: Changes in thymidine phosphorylase gene expression related to treatment of rectal cancer.
abstract: BACKGROUND
  The enzyme thymidine phosphorylase (TYMP) has tumor-promoting functions and its expression is often elevated in tumors.
  
  
  METHODS
  TYMP gene expression in tumorous and mucosal tissues was assessed using real-time polymerase chain reaction, in a study of patients with rectal cancer where chemotherapy and radiotherapy were given sequentially.
  
  
  RESULTS
  TYMP levels decreased after chemotherapy. For patients given radiotherapy, there was a significant increase in TYMP expression comparing biopsies before and after radiotherapy. The increase was also observed in the mucosa, although it was less pronounced.
  
  
  CONCLUSIONS
  Cancer treatment alters gene expression in tumor and adjacent mucosa of patients with rectal cancer. Chemotherapy may cause a decrease in TYMP gene expression, whereas radiotherapy, given as adjuvant treatment, causes a significant increase in expression. These results are of importance when interpreting TYMP expression data in rectal cancer and may be of clinical interest as TYMP participates in the activation of capecitabine.
authors.affiliation: Department of Surgery at the Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital/Ostra, Gothenburg, Sweden.
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Derwinger
authors.forename: Elinor Bexe
authors.initials: EB
authors.lastname: Lindskog
authors.forename: Erik
authors.initials: E
authors.lastname: Palmqvist
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Wettergren
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D003131:Combined Modality Therapy; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects; D005971:Glutamates / Q000627:therapeutic use; D006147:Guanine / Q000031:analogs & derivatives / Q000627:therapeutic use; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D000068437:Pemetrexed; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000532:radiotherapy / Q000628:therapy*; D013939:Thymidine Phosphorylase / Q000235:genetics* / Q000378:metabolism
chemical_list: D000964:Antimetabolites, Antineoplastic; D005971:Glutamates; D000068437:Pemetrexed; D006147:Guanine; C543750:TYMP protein, human; D013939:Thymidine Phosphorylase
keywords: Radiotherapy; capecitabine; chemotherapy; pemetrexed; rectal cancer; thymidine phosphorylase