text: user174: I'm starting for protein expression analysis. 
  In gene expression, we have TPM, RPKM etc. However, all I can see for protein expression is: "High", "Medium", "Low" and "Not detected".
  
  https://www.proteinatlas.org/ENSG00000140326-CDAN1/tissue
  
  
  Q: Is there a unit for measuring protein expression like gene expression? I've seen people talking about PE (protein existence). Can we use it for protein expression?
  
  user235: I would guess that the real unit for measuring protein expression would be pM (pico-moles) or a count of protein molecules.
  I'm not sure we have any methods to calculate such quantities though. 
  
original_text: 174: <p>I'm starting for protein expression analysis. </p>
  
  <p>In gene expression, we have TPM, RPKM etc. However, all I can see for protein expression is: "High", "Medium", "Low" and "Not detected".</p>
  
  <blockquote>
    <p><a href="https://www.proteinatlas.org/ENSG00000140326-CDAN1/tissue" rel="nofollow noreferrer">https://www.proteinatlas.org/ENSG00000140326-CDAN1/tissue</a></p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/TOng7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TOng7.png" alt="enter image description here"></a></p>
  
  <p>Q: Is there a unit for measuring protein expression like gene expression? I've seen people talking about PE (protein existence). Can we use it for protein expression?</p>
   235: <p>I would guess that the real unit for measuring protein expression would be pM (pico-moles) or a count of protein molecules.</p>
  
  <p>I'm not sure we have any methods to calculate such quantities though. </p>
  