Immunohistochemical profile and c-kit mutations in gastrointestinal stromal tumors

Solange Romagnoli, Daniela Graziani, Manuela Bramerio, Marcello Gambacorta, Piergiuseppe Colombo, Massimo Roncalli, Guido Coggi, Silvano Bosari

Research output: Contribution to journalArticlepeer-review

Abstract

Gastrointestinal stromal tumors (GISTs) are low-grade sarcomas arising from the interstitial cells of Cajal, harboring mutation of c-kit. We investigated the morphological, immunohistochemical, and molecular profile of 55 GISTs to establish the prevalence of mutations, their clinical significance, and diagnostic utility. c-kit mutations were investigated by evaluating the entire coding sequence of the gene with non-radioisotopic PCR-SSCP, and characterized with fluorescent cycle sequencing. Mutations were detected in 39 tumors (71%), the majority (67%) involving exon 11. Two tumors showed exon 9 mutations (one tumor located in the small intestine and one in the stomach), whereas two cases showed a polymorphism at the splicing site of exon/intron 1 present in healthy blood donors with a 3% frequency. CD117 was expressed in 53 tumors (96%); CD34 was positive in 42 cases (76%); 42 cases (76%) expressed both CD117 and CD34. c-kit mutations were similarly distributed in stromal tumors at low risk of aggressive behavior (78%), intermediate risk (66%), and high risk (71%). Fifteen tumors expressing CD117 showed wild-type kit gene, and on histological grounds, they were equally distributed among epithelioid and spindle cell morphology. One case neither expressed CD117 nor did it show c-kit mutation. Data suggest that both immunohistochemical and molecular evaluation may be useful in tumors likely to be classified as GISTs; molecular analysis appears valuable to support the diagnosis and to identify cases that can benefit from recent novel therapeutic tools.

Original languageEnglish
Pages (from-to)71-81
Number of pages11
JournalPathology Research and Practice
Volume201
Issue number2
DOIs
Publication statusPublished - Apr 8 2005

Keywords

  • c-kit mutation
  • CD117
  • CD34
  • GIST
  • Sarcoma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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