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Combined small‐cell carcinoma of the stomach: p53 and K‐ras gene mutational analysis supports a monoclonal origin of three histological components
Author(s) -
Han Bo,
Mori Ichiro,
Wang Xiaojuan,
Nakamura Misa,
Nakamura Yasushi,
Kakudo Kennichi
Publication year - 2005
Publication title -
international journal of experimental pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.671
H-Index - 72
eISSN - 1365-2613
pISSN - 0959-9673
DOI - 10.1111/j.0959-9673.2005.00424.x
Subject(s) - transversion , biology , laser capture microdissection , pathology , adenocarcinoma , stomach , point mutation , gene , microdissection , cancer research , mutation , microbiology and biotechnology , gene expression , cancer , genetics , medicine , biochemistry
Summary Primary small‐cell carcinoma (SmCC) is extremely rare in stomach. We reported an autopsy case of combined gastric SmCC with p53 and K‐ras mutational analysis. Histologically, the tumour was composed of well‐differentiated adenocarcinoma surrounding the central dominant SmCC component with scattered nests of squamous cell carcinoma. Immunohistochemically, all the neoplastic components revealed strong expression for p53 protein. Based on these findings, we hypothesized that these histologically different components originated from a same progenitor cell that possessed p53 mutation. Using Laser‐capture microdissection technique and mutational analysis, we identified the same point mutations of p53 gene (A→G transversion in codon 239) and K‐ras gene (G→A transversion in codon 13) in all the neoplastic components, but not in the adjacent normal gastric epithelium. Our results strongly support a hypothesis that the combined SmCC of stomach in this case was of monoclonal origin.