PROLIFERATION INDEXES OF VESTIBULAR SCHWANNOMAS BY KI-67 AND PROLIFERATING CELL NUCLEAR ANTIGEN

Two immunohistologic demonstrations of markers of proliferating cells, Ki-67 and proliferating cell nuclear antigen, were applied to tissues from 10 vestibular schwannomas. Each method demonstrated three distin ct rates of positively stained cells (p < .01 and p <.015, respectivel y, for each method). There was a one-to-one correspondence between the two immunohistologic methods in the assignment of cases to each growt h rate category except for two cases (Spearman rank correlation r = 0. 76, p <.05). These data support the concept of distinct growth rates i n vestibular schwannoma. Tissues were also sampled from different area s of the same tumor within nine samples. The results suggest that tumo r growth is not homogeneous within a tumor, but that proliferation may be more active near the surface.