Nanotech and cancer

Here’s news about using nanotech to develop extremely small and extremely sensitive devices to detect cancer biomarkers, mainly proteins. Universities like CalTech are devoting a lot of work to molecule-level early detection.

If you are among the third of the population who will someday develop cancer,
your body will contain warning signs well before your doctor is able to diagnose
the disease. If these subtle signals in your cells and your bloodstream could
only be detected sooner, you’d have a far greater chance of surviving. The
problem is that the changes that mark the early stages of cancer are remarkably
complex—and often slight, even on a molecular level.

But James Heath, a physical chemist at the California Institute of Technology,
believes that nanotechnology could finally provide the solution to this
molecu­lar riddle. Heath is betting that banks of ultrasmall silicon wires, each
made to detect a specific cancer-related protein, could pick up even the most
subtle changes in our body chemistry. The nanosensors that Heath and his Caltech
coworkers are developing will simultaneously look for hundreds or even thousands
of different biomolecules in, say, a drop of blood. If they work, these
nanosensors could be the basis for cancer tests that are not only more accurate
but, because they don’t involve tissue sampling and lab analysis, cheaper and
more convenient than those now available.

Heath is working with Lee Hood and the Institute for Systems biology to develop devices.

Systems biologists look at the cell much as an electrical engineer looks at a
complex circuit: as a highly interconnected system of components that switch
each other on and off and relay signals. Heath’s sensors might provide thousands
of clues to a person’s state of health, but Hood’s systems-biology approach is
needed to piece all those bits of information together into a coherent
picture.

Hood and his team have, for example, looked at how genes are expressed to
produce proteins in cells and tissues affected by prostate cancer. “Our idea,”
says Hood, “is that the difference between normal and diseased cells is that the
protein and gene regulatory networks in diseased cells have been perturbed, and
these disease perturbations are reflected in altered patterns of protein
expression controlled by the networks. A fraction of these perturbed proteins
will find their way into the blood and constitute molecular fingerprints that
are diagnostic not only of health and disease but of what disease and what type
of a particular disease.” (There are at least three different types of prostate
cancer, for example.)

“We have identified 300 [cancer marker] genes that are uniquely expressed in
the prostate,” says Hood, “and we predict that about 62 of these may be secreted
into the blood. We tested one of these by making antibodies against it and
demonstrated that it was only present in the blood of patients with prostate
cancer.” Hood’s team is now testing five more prostate cancer–secreted proteins.
It has also found a similar array of genes that should be diagnostic for ovarian
cancer.

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