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Posted on Sep 03, 2008, 5 a.m.
By Rich Hurd
New research published in the journal Science suggests that seemingly “normal” cells may carry cancer to new sites in the body long before a tumor develops.
New research published in the journal Science suggests that seemingly “normal” cells may carry cancer to new sites in the body long before a tumor develops.
Until now it was thought that secondary, or metastatic, cancer was a relatively late-stage event that only occurred when the disease was advanced. Recent research suggests that this theory is incorrect, and that cells can break off from a tumor before they become cancerous, thus evading detection by the immune system, and lie dormant in the body until key genes are activated.
Katrina Podsypanina and colleagues tested this theory on an experimental strain of mice. The genetically engineered mice possess dormant genes that trigger uncontrolled cell growth and division once they are switched on via exposure to the antibiotic doxycycline. Podsypanina took mammary cells from these mice and injected them into normal mice receiving doxycycline. Six weeks later, the researchers found metastatic cancer cells in the lungs – even though the mammary cells were not cancerous when they were injected. It was also found that the injected cells were capable of lying dormant for as long as 16-weeks.
The discovery explains why cancer often returns after the removal of a tumor. The researchers say that their research “refines our conception of cancer progression.”
Podsypanina K, Du YN, Jechlinger M, Beverly LJ, Hambardzumyan D, Varmus H. Seeding and Propagation of Untransformed Mouse Mammary Cells in the Lung. Published Online August 28, 2008. Science DOI: 10.1126/science.1161621; 2008.
