IL1R1 and mastocytosis: Among the relevant proteins identified in the Boruta model, high expression of MILR1, IL2-RA (CD25), IL-1RT1, and IL10 is in agreement with previous studies that have linked these markers to mast cell burden and/or mastocytosis,8,16,17,37 and may therefore be indicative of greater disease activity in patients with AdvSM rather than in patients with ISM.