title: Intestinal tumours induced in Apc(Min/+) mice by X-rays and neutrons.
abstract: OBJECTIVE
  To compare the development of intestinal adenomas following neutron and X-ray exposure of Apc(Min/+) mice (Apc - adenomatous polyposis coli; Min - multiple intestinal neoplasia).
  
  
  METHODS
  Adult mice were exposed to acute doses of X-rays or fission neutrons. Tumour counting was undertaken 200 days later and samples were taken for Loss of Heterozygosity (LOH) analysis.
  
  
  RESULTS
  Tumour numbers (adenomas and microadenomas) increased by 1.4-fold, 1.7-fold, 2.7-fold and 9-fold, after 0.5, 1, 2 and 5 Gy X-rays, respectively, and by 2.4-fold and 5.7-fold, after 0.5 and 1 Gy fission neutrons, respectively. LOH analysis of tumours from neutron-exposed mice showed that 63% had lost Apc and 90% (cf. 53% in controls) had lost D18mit84, a marker for Epb4.1l4a/NBL4 (erythrocyte protein band 4.1-like 4a/novel band 4.1-like 4), known to be involved in the Wnt (wingless-related mouse mammary tumour virus integration site) pathway. Some tumours from neutron-exposed mice appeared to have homozygous loss of some chromosomal markers.
  
  
  CONCLUSIONS
  X-ray or fission neutron irradiation results in strongly enhanced tumour multiplicities. Comparison of tumour yields indicated a low Relative Biological Effectiveness of around 2-8 for fission neutrons compared with X-rays. LOH in intestinal tumours from neutron-exposed mice appeared to be more complex than previously reported for tumours from X-irradiated mice.
authors.affiliation: Health Protection Agency, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxfordshire, UK. michele.ellender@hpa.org.uk
authors.forename: Michele
authors.initials: M
authors.lastname: Ellender
authors.forename: John D
authors.initials: JD
authors.lastname: Harrison
authors.forename: Emmy
authors.initials: E
authors.lastname: Meijne
authors.forename: Rene
authors.initials: R
authors.lastname: Huiskamp
authors.forename: Ryszard E
authors.initials: RE
authors.lastname: Kozlowski
authors.forename: Jackie W
authors.initials: JW
authors.lastname: Haines
authors.forename: Alan A
authors.initials: AA
authors.lastname: Edwards
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Ainsbury
authors.forename: John C
authors.initials: JC
authors.lastname: Moody
authors.forename: Simon D
authors.initials: SD
authors.lastname: Bouffler
authors.forename: Roger
authors.initials: R
authors.lastname: Cox
mesh_terms: D000818:Animals; D004307:Dose-Response Relationship, Radiation; D007414:Intestinal Neoplasms / Q000209:etiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D009502:Neutrons; D011829:Radiation Dosage; D012062:Relative Biological Effectiveness; D014965:X-Rays