GREM1 and neoplasm: Immunohistochemical staining of these proteins in biopsies from human OvCa peritoneal implants showed mesothelial‐derived (calretinin‐positive) spindle‐like cells in the stroma tissue surrounding tumour nodules, overlapping with areas with marked staining for MMP1, IL‐33, EGR1, TSP1, and GREM1.