Changes in the number of silver-stained nucleolar organizer regions in the normal, preneoplastic, and neoplastic endometrium.

The number of silver-stained nucleolar proteins (AgNORs) were counted in preneoplastic and neoplastic endometrial lesions and compared with those of the normal endometrium in the menstrual cycle. In glandular cells in the normal menstrual cycle, the mean number of AgNORs in the proliferative phase endometrium (3.4) was significantly higher than that in the secretory phase endometrium (2.5, p < 0.01). The mean number of AgNORs in well-differentiated endometrioid type adenocarcinoma (4.2) was significantly greater than that in simple hyperplasia (3.0, p < 0.001) and complex hyperplasia without cytological atypia (3.6, p < 0.05). The average number of AgNORs showed an increased tendency according to the neoplastic changes in the endometrium. These findings suggest that the one-step colloid method for AgNORs may therefore be a simple and partially useful technique for examining the proliferative activity in neoplastic and preneoplastic endometrial cells, but no clear distinction in each preneoplastic and neoplastic endometrial lesion can be drawn so far from our measurements.