MAPK1 and eosinophilic esophagitis: Interestingly, upon examination of transcript expression of signaling pathway proteins and apoptosis-related proteins such as ERK, JNK, Bcl-2, caspase 8, and Fas, for the newly diagnosed EoE subjects, it was found that the signaling pathway transcripts of ERK but not JNK were found to be increased relative to HC, UC, CD and treated EoE (Figure 1d).