Villin (MSVA-459R)

Villin is a 92.5 kDa protein encoded by the VIL1 gene located at the human chromosome 2q35. The protein is mainly localized in the microvilli of the brush border of various normal epithelial cell types. As an actin-binding protein, Villin is connected to the actin core bundle of the brush border. Villin has actin modifying functions and is involved in the nucleation, crosslinking, capping and splitting of actin filaments. Amongst others, the actin modifying functions are regulated by calcium and phosphorylation of the villin protein. Functional studies suggest an impact of Villin upregulation on the cytoskeleton architecture, cellular shape and motility as well as cell viability.

Villin staining pattern in Normal Tissues with antibody MSVA-459R (images are shown in our “Normal Tissue Gallery”)

Findings obtained by MSVA-459R are largely consistent to the RNA data summarized in the Human Protein Atlas (Tissue expression Villin). The MSVA-459R findings confirm that the most significant staining occurs in the distal gastrointestinal tract but show that a weak staining of surface epithelium also occurs in the stomach. In addition, our documentation describes weak to moderate villin expression in the epididymis caput that was not previously identified by RNA screening and assigns RNA expression data to specific cell types with protein expression such as acinar and ductal epithelial cells in the pancreas.

Suggested positive tissue control: Colon: A moderate to strong staining with predominance of the apical membrane should be seen in all epithelial cells. Liver: A weak to moderate staining of the apical pole of hepatocytes should be seen.

Suggested negative tissue control: Colon: Villin staining should be absent in all non-epithelial cells.

Normal tissue gallery

In carcinomas, villin expression is predominantly cytoplasmic. Villin positivity is most commonly seen in colorectal cancer. Tumors that were described to also show villin expression in a variable fraction of cases include gastric, duodenal and esophageal carcinoma, gastrointestinal neuroendocrine tumors, endometrial carcinoma, hepatocellular carcinoma, pulmonary adenocarcinoma (enteric type) and others.

The TCGA findings on Villin RNA expression in different tumor categories have been summarized in the Human Protein Atlas.

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. Accordingly, multiple different protocols can generate identical staining results.

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 9 Target Retrieval Solution buffer. Apply MSVA-459R at a dilution of 1:125 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent) according to the manufacturer’s directions

-Impact of pH

MSVA-459R results in strongest staining if pH9,0 is used for slide pretreatment. pH7,8 is acceptable but lower pH results in a significant reduction of sensitivity. 

The clinical/prognostic significance of villin expression in individual tumor types is unknown.