How breast cancer cells dodge immune system and surviveBy ANI
Wednesday, February 2, 2011
WASHINGTON - Scientists are one step closer to understanding how breast cancer progresses in real patients.
They have discovered a new way breast cancer cells dodge the immune system and promote tumor growth, providing a fresh treatment target in the fight against the disease.
Researchers found high levels of the protein Hsp27 (heat shock protein 27) are released from human breast cancer cells and may not only render immune cells unresponsive to the tumor, but increase blood flow to the tumor as well, both of which fuel tumor growth.
Past research reports Hsp27 is present in high levels inside breast tumor cells and is associated with resistance to chemo and radiation therapy.
De and his team discovered Hsp27 is also released, or pushed out of breast tumor cells, into the area surrounding the tumor, known as the breast tumor microenvironment.
Once outside the cells, Hsp27 may transform circulating white blood cells called monocytes that enter the tumor into cells known as macrophages, which do the opposite of what they are meant to do.
Usually, macrophages work to wipe out tumor cells, but in this case they help, rather than hurt, tumor cells.
In addition to suppressing the immune response to the tumor, these macrophages encourage rapid formation of extra blood vessels that can help in supplying blood to the tumor-a process known as angiogenesis-essentially feeding the tumor so it can continue to grow.
Elevated levels of Hsp27 have been found in the blood of cancer patients with other solid tumors, such as liver and pancreatic cancer tumors, leading study authors to believe the protein may play a role in tumor progression beyond breast cancer.
The findings have been published in the journal Cancer Research.(ANI)