Sheets of highly organized epithelial cells line all the cavities and free surfaces of the body, forming barriers that control the movement of liquids and cells in the body organs. The organized structure of normal breast epithelial cells may also serve as a barrier against cancer, according to a study by University of Helsinki scientists. The work appears in the journal Proceedings of the National Academy of Sciences.

Finnish researchers found that the tightly organized architecture of mammary epithelial cells is a powerful restraint against the cancer gene that provokes inappropriate proliferation. Their study also links function of a tumor suppressor gene to the development of cancer gene resistant epithelial organization.

"Rogue cancer genes can force epithelial cells to proliferate and proliferation of malignant cells will certainly disrupt the organized epithelial structure. However, there has always been this chicken or the egg problem: Does the cancer gene initiate cell proliferation, which causes disruption of the epithelial structure or does loss of tissue structure come first, creating suitable environment for cancer genes to enforce the cell cycle progression"" explains the research team leader Juha Klefstrom, Ph.D. The present study supports the idea that loss of tissue structure comes first.

The study demonstrates that organized epithelial structure can suppress malignant actions of cancer genes and identifies the LKB1 tumor suppressor gene as an architect of this proliferation resistant organizational plan. The ordered structure of epithelial cells is frequently lost in epithelial tumors, like breast carcinoma, and the study suggests that loss of structure may play a more active role in progression of tumors than previously anticipated.

SOURCES:
Proceedings of the National Academy of Sciences, online edition, August 27, 2007
University of Helsinki (http://www.helsinki.fi)