How to Measure Protein Expression

Protein expression measure can provide clues about the activities of the genes in your body, because proteins function as the final catalyst of cell activities. However, according to an article in the March 2010 issue of "LabMedicine," pathologists and biologists are yet to agree on brightfield microscopy or fluorescence microscopy as the most suitable method to measure protein expression. Whole-slide brightfield scanning is not only easy to use and provides chromogen stability, but it can protect glass slides longer.

Things You'll Need

• Cell tissue
• Slide
• Biotinylated secondary antibody
• Streptavidin-horseradish peroxidase
• 3,3'-Diaminobenzidine
• Color line-scan camera

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Instructions

• 1

  Place the cell tissue on a slide and add a biotinylated secondary antibody, followed by a streptavidin-horseradish peroxidase and wait for two minutes.

• 2

  Pour four drops of the 3,3'-diaminobenzidine on the specimen and wait for two minutes for the brown stain to spread wholly on the specimen.

• 3

  Place a histological section of the stained specimen on a motorized platform in a well-lit room. Carefully adjust the color line-scan camera to 20X or 40X magnification and scan the specimen. Align the stripes of the image and compress the digital image into a readable file size.

• 4

  Print the digital image for manual analysis or feed the image into computer software for technology-aided analysis. Observe the pattern of the stains as presented in the image. Carefully analyze protein expression based on the patterns of the stains on the specimen.

• 5

  Evaluate the protein expression on cancer cells and stroma by examining the concentration of protein expressed on the cell tissue.

• 6

  Use the color patterns to quantify the protein expression in a scale of 0 to 3+. Use the score to calculate HER-score or the Allred score.