title: FoxP3 demethylation is increased in human colorectal cancer and rat cholangiocarcinoma tissue.
abstract: OBJECTIVE
  FoxP3 expression is a marker for Tregs which are known to be involved in tumor immunity. We aimed to evaluate FoxP3 promoter demethylation in human colorectal cancer (CRC) and rat intrahepatic cholangiocarcinoma (ICC).
  
  
  METHODS
  Bisulfite-treated genomic DNA templates of shock frozen paired samples were studied from 13 anonymous CRC patients and from 10 male rats (n=6 ICC induced by thioacetamide and n=4 age-matched controls). Real-time PCR was carried out using a LightCycler 480 system. Human FoxP3 and CD3 promoter demethylations were estimated using previously described assays; and rat FoxP3 promoter demethylation using a newly developed assay.
  
  
  RESULTS
  A significant 3.5-fold increase of the demethylation in FoxP3 promoter region was found in human CRC and rat ICC (P<0.05). The average frequency of cells with FoxP3 demethylation in patients suffering from CRC was 0.26% in normal tissue and 0.92% in tumor tissue (n=11 paired samples). Although, no significant difference was found between the mean frequency of CD3 demethylation in normal tissue (4.80%, n=6) and in tumor tissue (4.14%, n=6) from CRC patients, the ratio of demethylated CD3/FoxP3 promoter areas was significantly lower in tumor specimens (P<0.05). Using our novel assay, we found a significant increase in mean frequencies of cells with FoxP3 demethylation in rats with ICC (7.42%, n=6) in comparison to controls (2.14%, n=4).
  
  
  CONCLUSIONS
  FoxP3 seems to be an interesting biomarker for immune response to epithelial tumors. Functional consequences from the increase of Tregs remain to be demonstrated. Further studies with outcome data are necessary.
authors.affiliation: Department of Gastroenterology and Endocrinology, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Frank Christian
authors.initials: FC
authors.lastname: Schultze
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Andag
authors.affiliation: Department of Gastroenterology and Endocrinology, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Salamah Mohammad
authors.initials: SM
authors.lastname: Alwahsh
authors.affiliation: Department of Medical Genetics, Medical University, Sofia, Bulgaria.
authors.forename: Draga
authors.initials: D
authors.lastname: Toncheva
authors.affiliation: Division of Oncologic Surgery, Aleksandrovska Hospital, Second Surgery Clinic, Sofia, Bulgaria.
authors.forename: Svilen
authors.initials: S
authors.lastname: Maslyankov
authors.affiliation: Division of Oncologic Surgery, Aleksandrovska Hospital, Second Surgery Clinic, Sofia, Bulgaria.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Yaramov
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: von Ahsen
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Brandhorst
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Philip D
authors.initials: PD
authors.lastname: Walson
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Oellerich
authors.affiliation: Department of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany. Electronic address: darinka.petrova@med.uni-goettingen.de.
authors.forename: Darinka Todorova
authors.initials: DT
authors.lastname: Petrova
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017252:CD3 Complex / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018281:Cholangiocarcinoma / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051381:Rats; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D017252:CD3 Complex; D004273:DNA, Neoplasm; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C500522:Foxp3 protein, rat; D009363:Neoplasm Proteins
keywords: CD3; Colorectal cancer (CRC); FoxP3; Intrahepatic cholangiocarcinoma (ICC); Promoter demethylation