The standard method is to count the positive staining. What if my staining needs to show loss of expression? Also, usually, when there is a loss of expression, there is a whole area of loss. I do not think calculating by Intensity X positive cells is a good indicator. Are there any other ways?
Hi
You could try calculating the area of positive staining (percentage of total) - you would need to decide a threshold above which the staining counted as positive - this would then decrease with increased loss of expression - crude but effective. Also you could look specifically at the areas showing loss of staining i.e. as regions of interest. These could be measured or counted ie.e x areas with loss of expression, X% loss of expression etc. It depends on whether or not the morphology of those areas is important.
Thank you for both answer. Philip, when you mentioned calculating for positive staining, do you mean if from the total area, i noticed 70% have loss of expression, then 30% is considered as positive staining? Konrad, I am doing FFPE samples from patients. I only have one sample per patient. Is there any other alternatives?
I agree - it may be that you have to identify and classify the various compartments of your sections and score appropriately. For example when we look at tumor sections we can classify according to necrotic, viable and invasive (EMT) compartment. Additionally we may look at a small panel of IHC stains (for proliferation, vascularisation, apoptosis etc). But sometimes a broad 'simple' count is enough...
no the samples are not homogenous. Philip, what do you mean broad 'simple' count?
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