Figure 2. Increased cell proliferative activity during IPMN progression.
a) Immunohistochemical staining of Ki-67 in IPMN lesions (×40). CIS, carcinoma in situ. b) The percentage of Ki-67-positive nuclear cells in IPMN lesions. The cell proliferative activity increased during IPMN progression, and the number of Ki-67-positive cells among malignant IPMNs (carcinoma in situ and invasive carcinoma) was significantly higher than that in non-malignant IPMNs (adenoma and borderline atypia) (p<0.0001). *, p<0.0001; **, p<0.001; ***, p<0.01.