title: High frequency of K-ras mutations in human colorectal hyperplastic polyps.
abstract: BACKGROUND
  Hyperplastic polyps are common benign colorectal polyps, and are thought to have little association with malignant tumours in the colorectum. However, several reports suggest that some hyperplastic polyps may develop into colorectal neoplasms.
  
  
  OBJECTIVE
  To clarify genetic alterations in colorectal hyperplastic polyps.
  
  
  METHODS
  Twenty eight colorectal polyps having serrated components were resected from patients endoscopically. The K-ras gene mutations in codons 12 and 13 were analysed by PCR-RFLP. Intranuclear p53 protein was immunostained by the avidin-biotin complex method.
  
  
  RESULTS
  A mutation of the K-ras gene was detected in nine (47%) of 19 hyperplastic polyps, and five (56%) of nine adenomas. p53 protein nuclear accumulation was detected immunohistochemically in two (22%) of nine adenomas, but not in any of the hyperplastic polyps.
  
  
  CONCLUSIONS
  Some hyperplastic polyps may be true neoplastic lesions, and could be precursors of malignant neoplasia.
authors.affiliation: Investigative Treatment Division, National Cancer Center Research Institute, Chiba, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Otori
authors.forename: Y
authors.initials: Y
authors.lastname: Oda
authors.forename: K
authors.initials: K
authors.lastname: Sugiyama
authors.forename: T
authors.initials: T
authors.lastname: Hasebe
authors.forename: K
authors.initials: K
authors.lastname: Mukai
authors.forename: T
authors.initials: T
authors.lastname: Fujii
authors.forename: H
authors.initials: H
authors.lastname: Tajiri
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Fukushima
authors.forename: H
authors.initials: H
authors.lastname: Esumi
mesh_terms: D000236:Adenoma / Q000737:chemistry / Q000235:genetics; D000368:Aged; D000369:Aged, 80 and over; D003108:Colonic Diseases / Q000235:genetics* / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000235:genetics; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D011127:Polyps / Q000235:genetics* / Q000378:metabolism; D012002:Rectal Diseases / Q000235:genetics* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D016159:Tumor Suppressor Protein p53