Expression of VEGF-A/C, VEGF-R2, PDGF-alpha/beta, c-kit, EGFR, Her-2/Neu, Mcl-1 and Bmi-1 in Merkel cell carcinoma

Mod Pathol. 2008 Jul;21(7):876-84. doi: 10.1038/modpathol.2008.63. Epub 2008 Apr 11.

Abstract

Merkel cell carcinoma is a rare but very aggressive tumor of the skin. With current treatment options, Merkel cell carcinoma is associated with a high incidence of recurrence and metastasis. Targeted anticancer therapies such as receptor tyrosine kinase inhibitors and antisense oligonucleotides have been found to be a promising new type of treatment for various types of cancer. To evaluate whether the use of targeted therapies is a possible treatment option in Merkel cell carcinoma, we determined the expression of the target molecules c-kit, Mcl-1, Bmi-1, vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF-receptor 2 (VEGF-R2), platelet-derived growth factor (PDGF)-alpha, PDGF-beta, epidermal growth factor receptor (EGFR) and Her-2/Neu in a tissue microarray of 32 samples of 29 patients with Merkel cell carcinoma. C-kit-positive samples were analyzed for mutations in exons 9 and 11. The tissue microarray was stained immunohistochemically with antibodies directed against the above-mentioned proteins, and an immunoreactivity score was calculated. DNA was extracted from c-kit-positive samples and was analyzed for exon 9 and 11 mutations using direct DNA sequencing. We found that c-kit (7%), Mcl-1 (88%), Bmi-1 (78%), VEGF-A (91%), VEGF-C (75%) VEGF-R2 (88%), PDGF-alpha (72%) and PDGF-beta (13%) were expressed in Merkel cell carcinomas. All samples showed a lack of EGFR and Her-2/Neu expression. Analysis of c-kit revealed no mutations. As VEGF-A, VEGF-C, VEGF-R2, PDGFs and c-kit are targets of new cytostatic agents used in the treatment of other cancers, inhibition by a multitargeted chemotherapy could be a very promising treatment option. High expression of Bmi-1 and Mcl-1 warrants further studies on the use of antisense oligonucleotides in Merkel cell carcinoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Austria / epidemiology
  • Biomarkers, Tumor / metabolism*
  • Carcinoma, Merkel Cell / metabolism*
  • Carcinoma, Merkel Cell / mortality
  • Carcinoma, Merkel Cell / secondary
  • DNA Mutational Analysis
  • Disease-Free Survival
  • ErbB Receptors / metabolism
  • Female
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Immunoenzyme Techniques
  • Male
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Neoplasm Proteins / metabolism*
  • Nuclear Proteins / metabolism
  • Platelet-Derived Growth Factor / metabolism
  • Polycomb Repressive Complex 1
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins c-kit / genetics
  • Proto-Oncogene Proteins c-kit / metabolism
  • Receptor, ErbB-2 / metabolism
  • Repressor Proteins / metabolism
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / mortality
  • Skin Neoplasms / pathology
  • Survival Rate
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • BMI1 protein, human
  • Biomarkers, Tumor
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Neoplasm Proteins
  • Nuclear Proteins
  • Platelet-Derived Growth Factor
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Repressor Proteins
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Polycomb Repressive Complex 1
  • ErbB Receptors
  • Proto-Oncogene Proteins c-kit
  • Receptor, ErbB-2