Doctors are often stymied in trying to prevent and treat the spread of malignant tumors throughout the body, not least when a tumor reappears in the original location after treating with surgery, drug or radiation. It has long been known that malignant tumor cells can send out ‘seed’ cells around the body to create new tumors. Now it turns out – as reported* in this week’s issue of Cell (links to abstract) – that these ‘circulating tumor cells’ (CTCs) can also return to their tumor of origin to re-seed and perpetuate that tumor’s growth. CTCs may even take ‘refuge’ in the bone marrow for a time before reappearing to seed or re-seed a malignant tumor. In migrating to a tumor, the CTCs seem to be responding to growth factors called interleukins, secreted by the tumor.
The reporting team, based at New York City’s Sloan Kettering Cancer Center and headed by top cancer researcher Dr. Joan Massague, studied the behavior of breast cancer cells labeled with a fluorescent marker to allow easy tracking, and then implanted into mice. The finds may help explain why tumors grow back after surgical removal and drug therapy and hopefully help inform development of future treatment approaches for malignant tumors.
* Mi-Young Kim et al. (2009) Tumor Self-Seeding by Circulating Cancer Cells. Cell, Volume 139, Issue 7, 1315-1326, 24 December 2009.
