Figure 2From: Cancer stem cells – the current status of an old concept: literature review and clinical approachesBasic tumour heterogeneity models. A - Clonal evolution model. High proliferation and genomic instability result in a large number of cells differing in genotype and thus phenotype. The best fitted cells are selected by Darwinian processes to generate clonal variants of the tumour. B - Cancer stem cell model. CSC population is capable of unlimited number of divisions. Tumour heterogeneity results from existence of phenotypically diverse populations of different stages of cell maturation.Back to article page