Abstract
A simple method has been developed which facilitates the detailed cytogenetic analysis of proliferating tumour cells within clusters and colonies arising from clonogenic tumour stem cells in biopsy samples of human cancers. The method uses a simple agar cloning technique for human tumours, which provides marked enhancement in the number of cases with observable mitotic activity and the number of mitotic figures available for detailed karyotypic assessment. The frequency of mitotic figures in cluster and colony samples is much greater than is attainable with standard chromosomal techniques. This novel approach should prove to be a powerful tool for the study of human tumour karyology.