PROC and Sepsis: However, phenotype size is known to be variable and phenotype 1 size is similar to the frequency of sepsis subclasses derived in the Molecular Diagnosis and Risk Stratification of Sepsis (MARS) cohort (34–41%), SENECA study (13–33%), and Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) trial (4–22%)5,12,17.