TNF is a prognostic marker in mastocytosis. (A) Comparison of TNF serum levels assessed by ELISA between subgroups of mastocytosis (cutaneous mastocytosis [CM], mastocytosis in the skin [MIS], indolent SM [ISM], and AdvSM). Results represent median and IQR. (B-D) Kaplan-Meier survival plots of the discovery cohort (B) and the validation cohort (C-D). Patients were stratified according to TNF serum level (cutoff values: 2.96 pg/mL in the discovery cohort and 1.235 pg/mL in the validation cohort based on different generations of the TNF ELISA) and analyzed for OS (B-C) and PFS (D). Differences in the probability of survival after specimen taking were analyzed. ∗∗P < .01.