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VEGFR-2 expression in human melanoma: Revised assessment
- Source :
- International Journal of Cancer. 129:2807-2815
- Publication Year :
- 2011
- Publisher :
- Wiley, 2011.
-
Abstract
- Vascular endothelial growth factor (VEGF) is an angiogenic factor that also functions as an autocrine growth factor for VEGF receptor (VEGFR)-2(+) melanomas. In multiple studies, VEGFR-2 was detected by immunostaining in 78-89% of human melanoma cells, suggesting that most patients with melanoma would benefit from anti-VEGF therapy. Here, we evaluated 167 human melanoma specimens in a tissue microarray to verify the presence of VEGFR-2, but found disparities in staining with commercial antibodies A-3 and 55B11. Antibody A-3 stained melanoma cells in 79% of specimens, consistent with published results; however, we noted extensive nonspecific staining of other cells such as smooth muscle and histiocytes. In contrast, antibody 55B11 stained melanoma cells in only 7% (95% confidence interval: 3.3-11.5) of specimens. As an internal positive control for VEGFR-2 detection, vascular endothelial cells were stained with antibody 55B11 in all specimens. We compared VEGFR-2(+) and VEGFR-2(-) melanoma cell lines by immunoblotting and immunohistochemistry after small interfering RNA (siRNA) knockdown and transient overexpression of VEGFR-2 to validate antibody specificity. Immunoblotting revealed that A-3 primarily cross-reacted with several proteins in both cell lines and these were unaffected by siRNA knockdown of VEGFR-2. In contrast, 55B11 staining of VEGFR-2(+) cells was mostly eliminated by siRNA knockdown of VEGFR-2 and increased in VEGFR-2(-) melanoma cell lines following transfection to express ectopic VEGFR-2. Our results show that relatively few melanoma cells (10%) express detectable levels of VEGFR-2, and therefore, the majority of patients with melanoma are unlikely to benefit from antiproliferative effects of anti-VEGF therapy.
- Subjects :
- Cancer Research
Immunoblotting
Biology
Antibodies
Article
chemistry.chemical_compound
Cell Line, Tumor
medicine
Humans
Neoplasm Metastasis
Autocrine signalling
Melanoma
integumentary system
Transfection
medicine.disease
Immunohistochemistry
Vascular Endothelial Growth Factor Receptor-2
Molecular biology
Vascular endothelial growth factor
Oncology
chemistry
Tissue Array Analysis
Cell culture
embryonic structures
cardiovascular system
biology.protein
Antibody
Immunostaining
Subjects
Details
- ISSN :
- 00207136
- Volume :
- 129
- Database :
- OpenAIRE
- Journal :
- International Journal of Cancer
- Accession number :
- edsair.doi.dedup.....1d27e931c4bc43986729258b5b743721