Summary The study was originally set up to measure accurate cell kinetic parameters in two murine squamous cell carcinomas (scc) for comparison with radiobiological data on proliferation during radiotherapy. The tumours, AT84 and AT478, were both moderately well differentiated aneuploid scc. In the course of the study, several Tumour cell kinetic studies are not only essential in investigating the many factors regulating proliferation but have also been shown to be useful for predicting the response to therapy (Silvestrini et al., 1984;Tubiana et al., 1989;Begg et al., 1992;Begg, 1993). Most cell kinetic studies have been carried out using either radio-labelled thymidine or a thymidine analog, which are incorporated into cells undergoing DNA synthesis. Such labelling of S-phase cells can be carried out in vivo or in vitro. In patients, administration of radiolabelled DNA precursors is precluded because of radiation hazards. Consequently, clinical studies have employed labelling of biopsy material in vitro (Silvestrini et al., 1984;Tubiana et al., 1989; The original goal of these studies was to measure accurately the cell kinetic parameters in two murine tumours for correlations with radiobiological characteristics of tumour proliferation during radiotherapy . The radiobiological data were available for tumours at two sizes, necessitating kinetic measurements at both these sizes. It was planned to use both FCM and IHC methods to ensure an accurate and correct description of the cell kinetics. The study was then also used to attempt to answer the questions posed above in these two well described animal tumour models. It thus provides comparisons of FCM and IHC methods, in vitro with in vivo labelling, single vs double labelling, the magnitude of intratumoural variations in kinetic parameters, in addition to the influence of tumour size.
Materials and methodsTumours and tumour growth rate AT84 and 478 are both fairly well differentiated murine squamous cell carcinoma lines, derived from spontaneous tumours of the oral and vaginal mucosa respectively. An early, more slowly growing (AT478/4) and a late, much faster (AT478/25) generation of one tumour line were compared.