Page History

1. Confirm actions
2. Background
   Two use cases:
   
   
   1. Prognostic stains - Primary cancer already determined.  Used for treatment decisions to be made.
      1. Pathologists knows where stain will/will not be expressed
      2. No need to declare location within cell that expresses the stain (nucleus, cytoplasm, membrane)
         
         
   2. Diagnostic stains - Used to differentiate between possible diagnoses.
      1. Where the protein is expressed informs the pathologist needed information to render a diagnosis.
      2. Need to declare location of protein expression in the cell.

Discussion was robust with discussion surrounding specific meaning of the observable (i.e., what is being measured by the pathologist) vs. how the observable and observations are interpreted by the pathologist.  For example, IHC scoring of HER2 in breast is 0,1+,2+.  However, clinical interpretation of HER2+ tissue based on the 0,1+,2+ has changed.  0 and 1+ are now considered NEGATIVE for HER2 and 2+ is considered equivocal.

For purposes of the observable entity concepts as exemplified by IHC HER2, interpretation of results is separate from the observation.  Therefore, a separate observable entity OR clinical finding should be used to represent the interpretation of the IHC staining observation (ordinal scale) in such situations.  Observable entities will be created to represent FISH and other testing methods used to realize the final diagnosis/interpretation

Scott Campbell to provide model examples of primary/met IHC

Also, focus to be on Synoptic vs. differential diagnostics.

Continue discussion:

What are we measuring when assessing "treatment effect"?  

Is this a histologic change?  Viability of tumor cells?