CA2 and necrotizing enterocolitis: Cardiac NEC ROIs were defined by enriched B cells (granular: pre-B cells) and mesenchymal cells (granular: follicular dendritic cells, interstitial cells of Cajal, and cycling stromal cells), and reduced CA2 (carbonic anhydrase 2)-, SLC26A2 (solute carrier family 26 member 2)-, and FABP1 (fatty acid-binding protein 1)-expressing epithelial cells compared with classical NEC ROIs (Figures S7B–S7D, S8B and S8C).