QualTek introduces a specially designed IHC protocol for the detection of membranous DR5 that may help investigators screen patients for DR5/Trail R2 agonist therapies. 

Conventional IHC methods are limited in that they only label cytoplasmic DR5 which can be expressed over a wide variety of cancers.  QualTek’s protocol labels membranous DR5 to which these therapies are specifically targeted. 

Similar to other predictive biomarkers such as Her2/neu, IGF1R and EGFR, this IHC method allows researchers more control over clinical trials by enrolling subjects who are DR5 membrane positive and therefore may be more likely to respond to targeted therapy.

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Representative Samples of BioMarkers

Growth Factors for Angiogenesis

The formation of new blood vessels– angiogenesis– is induced by the secretion of chemical signals from normal cells in the body. Among these chemical messages are VEGF (vascular endothelial growth factor) and FGF (fibroblast growth factor). Tumor cells can also induce the formation of blood vessels by producing, or overproducing, VEGF and FGF ligands. Such angiogenesis creates a new blood supply that can enable tumor cells to become malignant, allow their unlimited growth, and provide a mechanism for metastasis.

Because of their stimulation of angiogenesis, VEGF and FGF are the focus of many anti-angiogenic therapies. QualTek has developed immunohistochemistry (IHC) assays for the detection of several VEGF and FGF targets and their corresponding receptor proteins. Using our assays, we can determine the expression levels (ranging from low to high) of these proteins in various tumor tissues. We can also review clinical samples for changes in VEGF or FGF levels after treatment.

A digital image of VEGF staining in human colon carcinoma is shown here. VEGF is detected as a brown chromogen in granules or vesicles in the cytoplasm. This type of staining is consistent with a protein that is being secreted from the cell as a chemical signal.

CD31 is a valuable biomarker for the detection of blood vessels. CD31 or PECAM-1 (platelet endothelial cell adhesion molecule) is an integral membrane protein that is constitutively expressed on the surface of endothelial cells. Because blood vessels are lined with endothelial cells, visualizing CD31 in these cells means visualizing the blood vessels in a section of human or other animal tissue. More importantly, it can mean visualizing the prevalence of blood vessels surrounding and feeding an area of cancerous tissue. In this way, CD31 can be used as a measure of angiogenesis.

QualTek has clear and reliable IHC assays in place for the detection of CD31 in histological tissues. Our methods stain endothelial cells of blood vessels with a brown chromogen that allows for easy visualization within the tissue section. We have vast experience in the analysis of CD31 in xenografts and clinical samples and can provide comparative assessment of pre- and post-treatment samples. Digital images of CD31 staining in blood vessels in a human breast carcinoma tissue are shown below.

Analyzing Angiogenesis

VEGF staining in human colon carcinoma

Membrane Detection of DR5

CD31 staining in blood vessels in human breast carcinoma

Novel Assay Recently Developed by QualTek

CD31 staining in blood vessels in human thyroid carcinoma

DR5 staining in Pancreatic Cancer