Clustering of mitoses in human cervical carcinoma.

Mitotic nests have been noted both in tissue culture (Cone, 1968) and in human skin (Rowe and Dixon, 1975). The present paper is concerned with the disposition of mitoses in human tumor tissue. Mitotic indices, cell counts, and mitotic clusters were recorded in 20 carcinomas of the cervix uteri. The significance of the results was verified statistically. In 18 of 20 biopsies, the clustering of mitoses was in excess of chance at the 95% confidence level. Assuming a chance distribution, one would expect only one case (5% of 20 cases) to show significant clustering of mitoses. The incidence of cases which show mitotic clustering is higher in cervical carcinoma than in normal skin and uninvolved skin of psoriatic patients. The clustering phenomenon might be due to an initiating factor derived from a mitotic cell which propagates to other cells and activates them, or to a local deficiency in inhibitor factors which reversibly inhibit mitoses under normal conditions.