AGR2 and neoplasm: Many of these cells also stained for Agr2, a PDI family protein involved in mucin expression [32]; p-Erk-Tyr202/Thr204, a signaling kinase activated by protumorigenic signaling pathways [33]; and Yap1/Taz, transcriptional regulators important for PDAC initiation and progression [34] and for sustaining the activated state and fibroinflammatory responses of PaSC [35] in the tumor microenvironment.