Self-seeding found to promote cancer tumor growth and progression
An important study from Memorial Sloan-Kettering Cancer Center shows that cancer cells are able to self-seed, traveling back to the primary tumor. Cancer metastasis has been believed to occur when cancer cells leave the primary tumor and spread to distant organs. The process is a new finding.
By self-seeding, cancer cells promote further tumor growth, becoming more invasive to surrounding organs.
First author of the study Mi-Young Kim, PhD, Research Fellow in the Cancer Biology and Genetics Program at Memorial Sloan-Kettering says, "Our work not only provides evidence for the self-seeding phenomenon and reveals the mechanism of this process, but it also shows the possible role of self-seeding in tumor progression."
Finding ways to interfere with the self-seeding process that occurs when cancer cells recirculate back to the primary tumor could lead to new cancer treatments.
The researchers found that tumors send signals that attract like cancer cells, and re-infiltrate the primary tumor. Four genes were identified responsible for the ability of cancer cells to self-seed - IL-6 and IL-8 genes were found to attract like cancer cells, and FSCN1 and MMP1 were the genes found that mediate the infiltration process.
"We know there is an association between large tumor size and poor prognosis. This was always thought to reflect the ability of larger cancers to release more cells with metastatic potential. But this association may actually be caused by the ability of aggressive cancer cells to self-seed, promoting both local tumor growth and distant metastases by similar mechanisms", said study co-author Larry Norton, MD.
The researchers also note that breast cancer has the ability to self-seed, spreading to bones, lung, and brain, through the same gene expression pattern. Melanoma and colon cancer also showed the same self-seeding capability in additional experiments.