Two general ER stress and UPR markers, GRP78 and CHOP, were both up-regulated in A-NEC-XBP1s patients compared with A-NEC-XBP1u and R-NEC patients, which confirmed the occurrence of ER stress and the UPR in A-NEC-XBP1s patients. Here, HSPA5 is linked to necrotizing enterocolitis.