Interpretation of labeling indices in the presence of cell death.

A simple method is presented for the analysis of data on labeling indices in populations of cells undergoing division and apoptosis. The method is applicable to continuous, osmotic pump labeling experiments, and provides estimates of cell division rates. Cell replication kinetics play an important role in carcinogenesis, and the interpretation presented here should help in the incorporation of data on labeling indices into quantitative models for cancer risk assessment.