The microenvironment of a tumor cell has significant impact on cancer metastasis, revealed a new study by by Siyuan Zhang at the University of Notre Dame and a team at the University of Texas MD Anderson Cancer Center. This discovery has focused attention on fighting cancer in the tumor cell's microenvironment.

Researchers expected to see an increase of brain metastasis when PTEN, a known tumor-inhibiting protein, was artificially deleted in a tumor cell. Results were perplexing, sometimes there was even less metastasis in the brain, but the research group unexpectedly discovered that PTEN was reduced in tumor cells when they arrive in brain tissue. These findings suggested critical importance of the tissue environment, what Zhang calls the 'seed and soil' model- Tumors that grow in one kind of tissue would not grow in another easily. They need to adapt to the new 'soil'.

Zhang said, "By changing the soil, we potentially can suppress metastasis. The microenvironment has tremendous impact on how the gene is expressed, what type of gene will be expressed. It's definitely not due to genetic mutation. The point of this paper is we should not overlook the huge influence of the tissue architecture, the tissue environment, the tissue composition. It's a dynamic process."