Singer CF, Gschwantler-Kaulich D, Fink-Retter A et al.
Medical University of Vienna, Vienna, Austria.
Breast Cancer Res Treat 2008;110:273–81.
[2] Cancer associated fibroblasts stimulated by transforming growth factor beta1 (TGF-β1) increase invasion rate of tumor cells: a population study.
Casey TM, Eneman J, Crocker A et al.
Michigan State University, East Lansing, MI, USA.
Breast Cancer Res Treat 2008;110:39–49.
Editor’s note: At the most basic level, cancer results from the accumulation of mutations in susceptible cells. However, though necessary, this process of mutation accumulation is insufficient to give rise to clinically overt cancer. Mutations are common occurrences – it has been estimated that 7000 mutations occur over 50 cell divisions per year, or 140 mutations per cell division (
Breast Cancer Res 2001;3:299–303). Considering that each gram of tissue can contain 1 billion cells, the chances are high that some of them will acquire sufficient mutations for malignant transformation, yet only a few cells will develop into a cancer during an individual’s lifetime. Continuous growth into clinically detectable cancer requires cooperation of the microenvironment – i.e. the stroma – in order for tumor cells to receive stimuli and sufficient conditions to sustain their development.