Bcl-2 (MSVA-402M)

Bcl-2 (B-cell lymphoma 2) is the founding member of the bcl-2 family of proteins which all share a role in regulating apoptosis. The protein is coded by the bcl-2 gene on chromosome 18q21.33. Bcl-2 is a potent inhibitor of apoptosis. The protein is located at the outer membrane of mitochondria, where it inhibits the activity of pro-apoptotic proteins which often act at the mitochondrial membrane to promote its permeabilization. Alterations of the bcl-2 gene have been identified as a key driving event in cancer where high bcl-2 expression is a cause for poor prognosis and resistance to cancer treatments. Considering the pivotal importance of apoptosis for the homeostasis of all tissues, bcl-2 also has a role in many other disease types including neurodegenerative, cardiovascular, autoimmune, and infectious diseases. Bcl-2 is an emerging drug target. Venetoclax, a bcl-2 specific small inhibiting molecule, has been approved for the treatment of several neoplasms of hematopoietic and lymphatic tissues.

Images describing the Bcl-2 staining pattern in normal tissues obtained by the antibody MSVA-402M are shown in our “Normal Tissue Gallery”.

The findings described above are thus consistent with the the Human Protein Atlas (Tissue expression Bcl-2). Bcl-2 staining by MSVA-402M is preferentially seen in lymphatic cells (except germinal centres) but it also occurs in various other cell types. 

Positive control = Tonsil: A strong cytoplasmic bcl-2 staining should be seen in most interfollicular lymphocytes while most germinal centre cells are bcl-2 negative.

Negative control = Tonsil: The vast majority of lymphocytic cells from germinal centres must be bcl-2 negative while interfollicular lymphocytes are mostly positive.

Normal tissue gallery

Cancer tissue gallery

No data available at the moment

IHC users have different preferences on how the stains should look like. Some prefer high staining intensity of the target stain and even accept some background. Others favor absolute specificity and lighter target stains. Factors that invariably lead to more intense staining include higher concentration of the antibody and visualization tools, longer incubation time, higher temperature during incubation, higher temperature and longer duration of the heat induced epitope retrieval (slide pretreatment). The impact of the pH during slide pretreatment has variable effects and depends on the antibody and the target protein.

All images and data shown here and in our image galleries are obtained by the manual protocol described below. Other protocols resulting in equivalent staining are described as well.

Manual protocol

Freshly cut sections should be used (less than 10 days between cutting and staining). Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH 7,8 Target Retrieval Solution buffer. Apply MSVA-402M at a dilution of 1:150 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent) according to the manufacturer’s directions.

• The prevalence and clinical significance of bcl-2 expression in different cancer types is insufficiently explored.
• The role of bcl-2 in cells of the tumor microenvironment and its potential inhibition needs to be investigated.
• The potential of bcl-2 inhibition in subtypes of solid cancers needs to be investigated.
• The role of bcl-2 and its inhibition in neurodegenerative, cardiovascular, autoimmune, and infectious diseases needs to be explored.
  
  

There are two ways how the specificity of antibodies can be documented for immunohistochemistry on formalin fixed tissues. These are: 1. Comparison with a second independent method for target expression measurement across a large number of different tissue types (orthogonal strategy), and 2. Comparison with one or several independent antibodies for the same target and showing that all positive staining results are also seen with other antibodies for the same target (independent antibody strategy). 

Orthogonal validation: For the antibody MSVA-402M specificity is supported by the good concordance of the immunostaining data with data from three independent RNA screening studies, including the Human Protein Atlas (HPA) RNA-seq tissue dataset, the FANTOM5 project, and the Genotype-Tissue Expression (GTEx) project, which are all summarized in the Human Protein Atlas (Tissue expression Bcl-2). In particular, immunostaining by using MSVA-402M was highest in lymphatic tissues and in the thyroid but particularly low in the liver and the pancreas. However, because bcl-2 staining occurs in variable portions of inflammatory cells in all tissues, orthogonal validation based on data from disaggregated tissue is not sufficient for bcl-2 antibody validation.

Comparison of antibodies: True expression of bcl-2 in all cell types with documented bcl-2 immunostaining by MSVA-402M is validated by identical staining patterns obtained by a second, independent commercially available bcl-2 antibody, termed “validation antibody” for all analyzed tissues.

Normal tissue gallery