Molecular Assist to Cancer Surgeons
If you’ve contracted one of the common, nasty cancers of the large organs (lung, colon, breast, etc.), and it hasn’t spread yet, the best course is to cut it out. Surgeons do this pretty well if the tumor is clearly defined and easily discerned from normal tissue.
But if the surgeon misses a few malignant cells because the edges are hard to see, and he or she doesn’t want to chance removing any normal tissue in a vital organ—not good, because the cancer will likely grow back.
New work from Nobelist Roger Tsien’s lab offers a nice advance in more precisely visualizing tumors. Using a clever molecular trick, the UCSD group created an ingenious hybrid molecule possessing three properties in one: (1) it is fluorescent so can be seen by the surgeon; (2) it contains a paramagnetic ion that can be visualized by MRI; and (3) it carries a peptide that facilitates entry into cancer cells, but not the surrounding normal ones (Proceedings of the National Academy of Sciences 107: 9 [2 March 2010], 4317–4322).
Using four different mouse-tumor models, the group showed they leave 90% fewer residual malignant cells than is possible with conventional surgical methods. They were also able to increase the animals’ survival rate by up to five-fold. These are not small effects!
Although they haven’t performed the experiment, the authors speculate that the technique would also be amenable to increasingly important laparoscopic and robotic surgeries. Such techniques do not provide tactile feedback to the operator, so the increased visual clues from the fluorescent molecule should increase surgical success.
In the long run the answer to cancer is prevention, not cure. We aren’t very close to that point yet, so it’s comforting to know that clever chemistry is constantly providing advances that make the misery of a cancer diagnosis a little less bad.