title: Expression of p53 and p21 Ki-ras proteins in rat thyroid gland tumors induced by 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX).
abstract: BACKGROUND
  3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a disinfection by-product in chlorinated drinking water, induces follicular tumors in thyroid glands in Wistar rats. The mechanisms of the MX-induced thyroid gland tumorigenesis are not known.
  
  
  METHODS
  The expressions of p53 (primary antibody CM5) and p21 Ki-ras (primary antibody F234) proteins were evaluated by immunohistochemisty in MX-induced tumors in Wistar rats. p53 expression was studied in 3 follicular adenomas, 29 follicular carcinomas and two C-cell carcinomas of thyroid glands. p21 Ki-ras expression was studied in 13 follicular carcinomas and one C-cell carcinoma.
  
  
  RESULTS
  A weak expression of p53 protein (1-5% of tumor cells) observed in six follicular carcinomas (21%) and one C-cell carcinoma was not considered to be p53-positive. No expression of p21 Ki-ras was observed in any of the samples.
  
  
  CONCLUSIONS
  These data indicate that p53 and Ki-ras proteins are not overexpressed in the MX-induced thyroid tumors in rats.
authors.affiliation: Laboratory of Toxicology, National Public Health Institute, Kuopio, Finland.
authors.forename: Pasi
authors.initials: P
authors.lastname: Hakulinen
authors.forename: Veli-Matti
authors.initials: VM
authors.lastname: Kosma
authors.forename: Hannu
authors.initials: H
authors.lastname: Komulainen
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D005663:Furans / Q000633:toxicity*; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013964:Thyroid Neoplasms / Q000139:chemically induced* / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*
chemical_list: D002273:Carcinogens; D005663:Furans; D016159:Tumor Suppressor Protein p53; C054121:3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone; D016283:Proto-Oncogene Proteins p21(ras)