Thread by @Path_Matt

I am putting together a talk on PD-L1 and I have developed some cartoons to help describe the different scoring systems and provide a visual easy to understand picture of how #Pathologists interpret PD-L1

There are three major scoring systems that are used for PD-L1
TPS (Tumor proportion score)
CPS (Combined Positive Score)
IC (Immune cell score)
We can use cartoons to conceptualize what these mean.

We can then build a cartoon version of a tumor to help understand how these PD-L1 scores may differ between tumors and the challenge in interpreting them
Lets start with the TPS score

What do you think is the PD-L1 TPS score for this case?

Answers will be at the end, lets move on to the next CPS score.
Note: The tumor cartoon is the same between the two images

What is the PD-L1 CPS score for this case?
Remember it is not a percent but a "score"

Lastly lets do the same IC score for the tumor.

What is the IC score for this tumor?

Ok lets make it a bit easier;

As you can see the PD-L1 score varies based on the scoring system that you use.

This is a simplified example where there are only 17 tumor cells to count. In real cases the minimum number of cells for most assays is 100 cells. In many cases the #pathologist must look at slides that contain thousands of tumor cells and generate an overall score for the tumor

I hope this mini-tweetorial is useful.

Feel free to use and share my cartoons. Share them with non-pathologist colleagues and let them try to score PD-L1.

@smlungpathguy @IHC_guy @SansanoValero @raghupillappa @MelanieBoisMD @TristanRutland7 @natasharekhtman @thoracicpath

I should also mention that the CPS score is the fraction multiplied by 100