Intracellular position of G2/M-phase nuclei in neoplastic and non-neoplastic pseudostratified glands suggests the occurrence of interkinetic nuclear migration.

ABSTRACT

It has been established that nuclear pseudostratification of the neural epithelium in vertebral embryos is caused by interkinetic nuclear migration, a cell cycle-dependent regulation of nuclear movement, during which the G2/M-phase nuclei move apically before returning basally in the G1/S phase. Here we demonstrate the cell cycle-related nuclear location characteristic of interkinetic nuclear migration in human neoplastic and non-neoplastic pseudostratified glands. Immunohistochemical analysis with phosphohistone H3 (a G2/M-phase marker) and Ki67 was performed on fetal tissues, proliferative-phase endometrium (5 cases), and colonic adenomas (12 cases). In all cases, G2/M nuclei were significantly located apically, whereas Ki67-positive nuclei were widely distributed along the basal-apical axis. In the proliferating zone of the normal colon mucosa, elongated nuclei in the G2/M phase were occasionally found on the apical side of the cells. These results suggest that the interkinetic nuclear migration occurs in association with cell proliferation in both neoplastic and non-neoplastic glands.