title: Ki-ras gene mutations are invariably present in low-grade mucinous tumors of the vermiform appendix.
abstract: OBJECTIVE
  Low-grade mucinous tumors of the appendix appear to have a simple histological structure. Paradoxically, reports have suggested a greater frequency of Ki-ras gene mutation in these lesions than in more complex lesions such as benign colonic adenomas and carcinomas. We assessed several molecular genetic changes, including Ki-ras gene mutations, in a large series of low-grade mucinous tumors of the appendix.
  
  
  METHODS
  We retrospectively ascertained low-grade mucinous tumors of the appendix from computerized pathology records. Extracted DNA was analyzed for APC and DCC gene loss of heterozygosity, microsatellite instability and for the presence of Ki-ras gene mutation using standard molecular techniques. Controls consisted of normal appendices, other appendiceal neoplasms, and ovarian mucinous cystadenomas.
  
  
  RESULTS
  A total of 31 low-grade appendiceal mucinous tumors were identified. All were microsatellite stable and none demonstrated loss of heterozygosity for the APC or DCC genes. By contrast, all 31 lesions contained a Ki-ras gene mutation.
  
  
  CONCLUSIONS
  The presence of a Ki-ras gene mutation in all lesions, with no other molecular changes identified, strongly suggests a possible etiological role of the Ki-ras mutation in the development of this particular lesion of the appendix. Based on other work regarding intestinal bacteria, we hypothesize a relationship between chronic inflammation of the appendix from bacterial overgrowth and Ki-ras gene mutation.
authors: Department of Pathology, Saint Barnabas Medical Center, Livingston, NJ 07039, USA. pzauber@gmail.com
authors: Peter
authors: P
authors: Zauber
authors: Errol
authors: E
authors: Berman
authors: Stephen
authors: S
authors: Marotta
authors: Marlene
authors: M
authors: Sabbath-Solitare
authors: Timothy
authors: T
authors: Bishop
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics; D018253:Adenoma, Villous / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000235:genetics* / Q000473:pathology; D002276:Carcinoid Tumor / Q000235:genetics; D018291:Cystadenoma, Mucinous / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm; D005260:Female; D017491:Genes, APC; D016163:Genes, DCC / Q000235:genetics; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D007417:Intestinal Polyps / Q000235:genetics; D019656:Loss of Heterozygosity / Q000235:genetics; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D004273:DNA, Neoplasm