Cell cycle parameters in human solid tumors.

Abstract

Tumor cell kinetic parameters were studied in eight patients with solid tumors following intravenous (i.v.) [3H] thymidine injection, 0.2 mCi/kg. The studies were performed to determine the variability in labeling index (LI) within and among lesions from the same patient, among lesions from different patients with the same disease, and to determine the variation in cell cycle kinetic parameters from lesion to lesion in the same patient. The variation in LI and percent labeled mitosis (PLM) was determined from multiple biopsy or aspirate specimens obtained at intervals following administration of [3H] thymidine. In 11 separate tumor lesions the intralesional LI varied from 20% to 405% with a mean variation of 97%. The intralesional LI of nine of the 11 lesions varied by less than 100%. In four patients multiple LI were determined from each of several lesions. The mean LI from lesion to lesion varied from 10% to 276%. In three of the four patients the variation was ≪34%. These data suggest that there may be less interlesional than intralesional variation when mean LI are compared and that three to five samples per lesion may provide representative LI in patients with solid tumors. In two patients, one with carcinoma of the breast and one with carcinoma of the lung, PLM curves were obtained by sampling two and three lesions, respectively. The results from both patients indicate little interlesional heterogeneity in cell cycle distribution. For the patient with lung cancer the Ts and TG2+M were estimated to be 16.5 and 7.5 hours, respectively. For the patient with breast cancer the Ts and TG2+M were estimated to be 18 and and 10 hours, respectively. For both patients the Tc was estimated to be >100 hours. These data have been compared to existing cell kinetic data in lung and breast cancer.