Immunohistochemical staining in AAC, ACC and normal gallbladder mucosa. (a) Ki67 expression in acute acalculous cholecystitis (AAC). (b) One M30-positive apoptotic cell in AAC. (c) Hypoxia-inducible factor (HIF)-1α expression in AAC; nuclear expression and moderate cytoplasmic expression can be seen in this sample. (d) Abundant Ki67 expression in acute calculous cholecystitis (ACC). (e) two M30-positive cells in ACC. (f) strong nuclear expression of HIF-1α in ACC. (g) Ki67 in control sample. (h) M30-positive cell in control sample. (i) Abundant nuclear and weak cytoplasmic expression of HIF-1α in control sample.