Cancer that spreads from one body part to another is a particular risk to patients, but understanding why certain cancers spread, or metastasize, could give doctors clues about how to stop them and save lives.

Researchers are getting closer. A study in Cell Reports says that a protein is found in larger numbers in certain cells associated with breast cancer metastases — called mesenchymal stem cells or MSCs — and details how the protein encourages the cancer to spread and grow by facilitating communication between them and cancer cells. Those MSCs have already “been shown to promote the growth and metastatic ability of breast cancer and other human malignancies, but the mechanisms are incompletely understood,” according to the study. The problem protein, DDR2, serves as a sort of organizational leader.

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The team had examined samples of metastases from cancer patients and later mice. When DDR2 “was present in cells, the researchers could see an orderly and efficient migration in which cancer cells, mesenchymal stem cells and collagen neatly align to form a metastasis,” according to a statement from the University of Michigan. The rodents without DDR2 “formed fewer metastases and showed no signs of the orderly alignment of cells.”

Developing a drug that inhibits DDR2 could be a useful tool in controlling breast cancer and preventing it from spreading to other parts of the body.

About 20 percent of breast cancer patients get these metastases, which “are the main cause of death,” the study says. “Inhibiting metastatic spread or halting the growth and invasiveness of established metastasis improves survival.”

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The American Cancer Society says lymph nodes under the arm are a common place for breast cancer to spread to, because usually cancer metastasizes to a location “downstream” from the original tumor site. An organ or body part downstream of the original cancer is somewhere the malignant cells can be carried by the blood, for example, and new tumors can grow where they settle.

“Likewise, there are many cancers that commonly spread to the lungs,” the group says. “This is because the heart pumps blood from the rest of the body through the lungs’ blood vessels before sending it elsewhere. The liver is a common site of spread for cancer cells that start in the colon because blood from the intestines flows into the liver.”

Source: Kleer CG, Gonzalez ME, Martin EE, et al. Mesenchymal Stem Cell-Induced DDR2 Mediates Stromal-Breast Cancer Interactions and Metastasis Growth. Cell Reports. 2017.

See also:

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