Two articles on Evolution and Cancer

Clonal evolution in cancer

Mel Greaves & Carlo C. Maley

Nature 481, 306–313 (19 January 2012) doi:10.1038/nature10762

Abstract
Cancers evolve by a reiterative process of clonal expansion, genetic diversification and clonal selection within the adaptive landscapes of tissue ecosystems. The dynamics are complex, with highly variable patterns of genetic diversity and resulting clonal architecture. Therapeutic intervention may destroy cancer clones and erode their habitats, but it can also inadvertently provide a potent selective pressure for the expansion of resistant variants. The inherently Darwinian character of cancer is the primary reason for this therapeutic failure, but it may also hold the key to more effective control.

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Cancer stem cells: an evolving concept

Long V. Nguyen, Robert Vanner, Peter Dirks & Connie J. Eaves

Nature Reviews Cancer , | doi:10.1038/nrc3184 (not open access)

Abstract

The cancer stem cell (CSC) concept derives from the fact that cancers are dysregulated tissue clones whose continued propagation is vested in a biologically distinct subset of cells that are typically rare. This idea is not new, but has recently gained prominence because of advances in defining normal tissue hierarchies, a greater appreciation of the multistep nature of oncogenesis and improved methods to propagate primary human cancers in immunodeficient mice. As a result we have obtained new insights into why the CSC concept is not universally applicable, as well as a new basis for understanding the complex evolution, phenotypic heterogeneity and therapeutic challenges of many human cancers.