AGR2 and neoplasm: Remarkably,, tumor organoid formation was restored when AGR2-depleted tumor organoids were supplemented with AGR2-SXXS (thioredoxin inactive), but not in the presence of reducing agent This result suggests a protein-protein interaction between eAGR2 and ECM proteins and/or proteins involved in the control of cell adhesion and cell-matrix interaction in an AGR2 thioredoxin-like domain independent fashion.