Cell kinetics and in vitro clonogenicity of primary colorectal cancer: clinicopathological relationships and the implications for chemotherapy.

Cells with the capacity for clonogenic growth in vitro can be isolated from primary human colorectal carcinomas. In this study colonies were grown, composed of cells which expressed epithelial membrane antigen and CEA, confirming their neoplastic character. Adequate growth for assessing the cytotoxicity of drugs for use in clinical chemotherapy regimes was obtained from 64% of the specimens. Colony forming efficiency of the tumour cells was not related to clinical stage or pathological grade of the parent tumour. The S-Phase fraction of the tumour was established in vitro using pulse thymidine labelling. The thymidine labelling index for Dukes' stage A and B tumours was significantly higher (median 15.7%, range 10.1-23.6%) than for Dukes' stages C and D (median 11.7%, range 0.1-13.6%). Colony forming efficiency in vitro was independent of the thymidine labelling index of the tumour. These findings are discussed with reference to the known heterogeneity of colorectal adenocarcinomas.