Tyrosine kinase receptor expression in thymomas

J Cancer Res Clin Oncol. 2004 Apr;130(4):222-4. doi: 10.1007/s00432-004-0545-z. Epub 2004 Feb 5.


Purpose: Promising new therapies for neoplasia include tyrosine kinase receptor antagonists. Tyrosine kinase oncogenes present an appealing anti-tumor drug target since they play an integral role in a variety of cellular responses including cell proliferation and differentiation. We previously demonstrated a high rate of epidermal growth factor receptor (EGFR) expression in advanced-stage thymic epithelial tumors. More recently, we have examined c-KIT (CD117) expression in a similar series of tumors.

Methods: Tumor from 35 patients seen at our institution for treatment of advanced-stage thymoma was available. Twenty thymomas and 15 thymic carcinomas were assessed for c-KIT expression. Tissue sections of tumor were stained immunohistochemically with anti-c-KIT (Oncogene). Either cytoplasmic or membrane staining was considered positive. Appropriate controls were performed. Positive staining for c-KIT was present in 12 tumors (11 thymic carcinomas and 1 thymoma).

Results: In distinction to EGFR, c-KIT is expressed more commonly in thymic carcinomas (73% of carcinomas) than in thymoma (5% of thymomas).

Conclusions: An EGFR negative/c-KIT positive staining pattern is typical of thymic carcinoma, whereas thymomas are generally EGFR positive/c-KIT negative. Possible therapeutic implications of these observations remain to be determined.

MeSH terms

  • Carcinoma / chemistry*
  • Carcinoma / secondary
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunohistochemistry
  • Proto-Oncogene Proteins c-kit / analysis*
  • Proto-Oncogene Proteins c-kit / immunology
  • Receptor Protein-Tyrosine Kinases / analysis*
  • Thymoma / chemistry*
  • Thymoma / secondary
  • Thymus Neoplasms / chemistry*
  • Thymus Neoplasms / pathology


  • Proto-Oncogene Proteins c-kit
  • Receptor Protein-Tyrosine Kinases