Abstract
The quantitative aspect of apoptosis in experimental tumors is often neglected. In this study, the apoptotic and mitotic indices for a range of tumors have been determined at light microscope level. It has been found that the apoptotic levels fall into a consistent range for all tumor types and agree well with those described by previous workers. It is suggested that these might be basic parameters of tumor expansion, as relevant to growth kinetics as mitotic levels.