Clonality of combined tumors

Arch Pathol Lab Med. 2002 Apr;126(4):437-41. doi: 10.5858/2002-126-0437-COCT.

Abstract

Context: Tumors with mixed morphologic patterns (combined tumors) are sometimes encountered, and questions often arise regarding the mechanism of molecular pathogenesis of each component and their relationships.

Objective: To determine whether different components of combined tumors contain the same or different genetic alterations, thus providing evidence for their clonality.

Materials and methods: Six combined tumors with 2 components (in each case, both components showed epithelial differentiation morphologically) were studied by microdissecting tumor cells from each morphologic area followed by loss of heterozygosity analysis.

Results: In 1 of the cases studied, the different morphologic areas contained different patterns of genetic alterations. In the remaining 5 cases, the different morphologic areas harbored identical genetic changes in the chromosome regions studied. The latter group, interestingly, included a colonic tumor with an area of tubulovillous adenoma and an area of neuroendocrine carcinoma, and 2 lung tumors with squamous carcinoma and small cell carcinoma components.

Conclusions: Our results suggest that in the majority of combined tumors, cells with different phenotypes share similar genotype and may arise from a single precursor cell. However, in a minority of these tumors, different areas may be derived from different precursor cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics*
  • Adenocarcinoma / pathology
  • Adenoma, Villous / genetics
  • Adenoma, Villous / pathology
  • Aged
  • Carcinoma, Neuroendocrine / genetics
  • Carcinoma, Neuroendocrine / pathology
  • Carcinoma, Small Cell / genetics
  • Carcinoma, Small Cell / pathology
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / pathology
  • Clone Cells / pathology*
  • Colonic Neoplasms / genetics*
  • Colonic Neoplasms / pathology
  • DNA, Neoplasm / analysis
  • Female
  • Genes, p53
  • Genes, ras
  • Humans
  • Loss of Heterozygosity
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Male
  • Microsatellite Repeats
  • Middle Aged
  • Mutation
  • Neoplasms, Multiple Primary / genetics*
  • Neoplasms, Multiple Primary / pathology
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length

Substances

  • DNA, Neoplasm