Human breast tumors' 'microenvironment' primes them for ...( The environment within primary breas...),Health

The environment within primary breast tumors can empower cells that break free and enter the bloodstream to successfully invade other organs, researchers report in the April 4th Cell, a publication of Cell Press.

Specifically, through studies of hundreds of human breast tumors, the researchers found evidence that the cytokine TGF in the tumor microenvironment primes breast cancer cells for metastasis to the lungs, one of the most common sites for the spread of breast and other cancers. TGF signaling is often activated within tumors as a natural response to the oxygen starved and inflammatory conditions that come with tumor progression.

The microenvironment of a tumor is not just cancer cells, but all other cell types that congregate there, said Joan Massague of Memorial Sloan-Kettering Cancer Center in New York. In recent years, he said, increasing attention has been paid to the impact those other body cells can have on the tumor locally, through their affects on blood vessel growth, the ability of cancer cells to enter the circulation, and so on.

Our study shows that it doesnt end there, he said. The cancer cells can come out with instructions that serve them in the long run.

The research team analyzed the expresssion of all 20,000 genes in the human genome within hundreds of primary breast tumors. Those tumors fell within two classical groups based on whether their estrogen receptor status was positive or negative (ER+ or ER-). In both tumor groups, the researchers found that about 40 percent of the tumors bore the genetic signature of TGF?s influence.

They found that TGF exposure didnt seem to make any difference to the risk of cancer spread in ER+ tumors. In ER- tumors, however, TGF correlated markedly with an increased risk for metastasis to the lung, but not to bone. In other words, Massague said, context matters."

The researchers continued to dig, ultimately uncovering the fascinating biology behind tha
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