Metaphase-arrest technique applied to human cervical epithelium. II. Cell production rates in normal and pathological cervical epithelium.

An application of the metaphase-arrest technique to human cervical epithelium, in vivo, was utilized to obtain cell birth rate data for seventy-six patients with normal and pathological cervical epithelium. Mean cell production rates for basal and parabasal layers of normal epithelium were 0.91 and 0.92 cells/1000 cells/hr respectively. Histologically normal epithelium adjacent to CIN (cervical intra-epithelial neoplasia) had a significantly higher rate for the parabasal layer compared to the 'normal' group (P less than 0.05). Values for the lower two-thirds of CIN III were 8-10 times higher than for normal epithelium, with microinvasive carcinoma having the highest rates of all. Values for wart-affected cervical epithelium (NCWVI) were intermediate between normal and CIN, but there was activity in the superficial layer, possibly reflecting activity of the papilloma virus. Large variation in birth rates between individuals in the same histological category was noted for each group, this being particularly the case in six patients with early invasive carcinoma. The data is used to attempt to elucidate some of the uncertainties surrounding the aetiology and biological behaviour of cancer of the cervix and its precursors. Sources of inaccuracy are emphasized and practical difficulties discussed.