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New Nanotech Helps Detect Early-Stage Cancer
CWmike writes "Stanford University researchers have used nanotechnology and magnetics to create a biosensor that they said should be able to detect cancer in its early stages. The sensor, which sits on a microchip, is 1,000 times more sensitive than cancer detectors used clinically today, say scientists at Stanford. The researchers announced this week that the sensors have been effective in finding early-stage tumors in mice, giving them hope that it can be equally successful in detecting elusive cancers in humans. 'In the early stage [of a cancer], the protein biomarker level in blood is very, very low, so you need ultra-sensitive technology to detect it,' said Shan Wang, professor of materials science and engineering at Stanford. 'If you can detect it early, you can have early intervention and you have a much better chance to cure that person.' Wang also noted that the biosensor could be used to determine whether chemotherapy or other cancer treatments are working after only a few days."
and not a pile on nonsensical garbage, the wang group page has a good description of the project.
Essentially they're using magnetic nanoparticles covered with antibodies to detect the binding of some tumor biomarkers. While the idea is interesting, there's no indication (yet) that its more sensitive than other biomarker assays, although it very well may be. Fluorescence techniques can get down to the tens of molecules level of sensitivity (which is insanely impressive). If they can get even lower, I'd be extremely impressed, but I can't find any published data on their immunoassays. Their comments about capturing and sorting out cancer cells is a bit odd. If you're looking to isolate whole cells based on recognizing protein biomarkers, I can't see any advantages of their tech over standard fluorescence activated cell sorting (FACS), unless their assays are really more sensitive.
Really, the only thing of interest in this work is using the magnetic properties of their nanoparticles to detect binding. I would be really curious to see if this could supplant technologies like quartz crystal microbalances that look for changes in the vibrational modes of a crystal to detect surface binding events as being simpler and less prone to disruption by temperature fluctuations, doors opening or people walking by. The biomarker assay is interesting but by no means genuinely new technology- only the detection method is truly novel. Not bashing the work done here, the binding assay is really cool, the application looks like it was mostly thought of to get grant money.
If this device is 1000x more sensitive than anything we've had before, it seems to me that we have no real data about how such a low level corresponds to actual cancer risk.
It's been well known for decades that cancer cells are commonly created in the body. Most of the time the immune system takes care of them before cancer gets a foothold. One question I have is, will this sensor be so sensitive it'll detect the normal everyday cancer that our immune system would normally fight off by itself? This could lead to un-necessary intervention, which can cause more harm than good.
AccountKiller
Cancer can affect the levels of various proteins in the blood: prostate cancer can raise prostate specific antigen, carcinoembryonic antigen is associated with colon and other cancers, alpha-fetoprotein is associated with liver and other cancers... the list goes on and on.
The problem is that these proteins are produced by normal cells but cancer cells often produce them in excess. The ability to detect these proteins has never been a problem. The problem is that they often only reach a very high level when the cancer has spread. The only protein used in cancer screening is prostate specific antigen and the benefit of this test is very contentious as its use has resulted in many a false negative and false positive diagnosis.
A real discovery would be to identify a blood marker that is useful for screening. It must be sensitive enough to enable detection while the cancer is curable but still maintain a very low false positive rate - as of today this doesn't exist for any cancer.
I'm part of this research and I'm pleasantly surprised someone posted it on Slashdot. To answer some questions: The device is indeed a concentration-measuring chip (not just positive / negative, which would be simpler), and in a just-posted Nature Medicine paper it shows that the signal vs. concentration curve goes 1000x farther on the low end (and the high end too, i.e. more dynamic range) before blending in with the background than the same assay (and antibodies) used on ELISA. Plus, it is a simple device that performs identically in saliva, urine, different pH and temperatures, and which is generally rugged and not too picky about the experimental conditions. This is quite helpful too.
Another point of the publication is that this device can measure small but slowly increasing tumor marker concentrations in lab mice which are known to have cancer. The key is that these tumor markers can be measured with this chip, but are too small in concentration for the traditional platforms such as ELISA. This means you can (in mice, at least) get important early cancer growth trend information (from a blood test) which you probably wouldn't have been able to obtain before.
Just published in Nature Medicine Advanced Online publications (unfortunately requires subscription):
http://www.nature.com/nm/journal/vaop/ncurrent/abs/nm.2032.html
Technical Report abstract
Nature Medicine
Published online: 11 October 2009 | doi:10.1038/nm.2032
Matrix-insensitive protein assays push the limits of biosensors in medicine
Soon, cancer treatment will be highly specialized and tailored to the individual and the cancer or cancers he/she has. This and other technologies can be used to dynamically adjust the patients treatments in essentially real time. If an emerging resistant strain(s) is detected or found to be emerging, then potent and thought out combination therapy can be used to control or destroy the cancer. Combination therapy will have to be engineered in such a way that it's mathematically as infeasible as possible for newer multi resistant strains to emerge.
Perhaps drugs themselves could test a cell or blood or anywhere in vitro i guess for biomarker(s) and then adjust its structure according to what has been encountered so it can effectively treat it. The simpler thing is so that it tests a cell for a cancer marker first and then blocks or kills it if it is dangeorous .. or it can use multiple criteria. Let me give you an example .. if a certain type of cell .. say in the liver has markers of being kidney origin .. then it could be a cancer cell and the drug can destroy it. This can also be used to treated auto immune problems or infectious diseases. Some progress is being made to this kind of smart drug design .. recently someone announced the can do an AND operation.
Cancer drugs will need to be designed on the fly in the future. As in, if you have a certain cancer, the drug may have to be designed specifically for your cancer based on its genetic profile. What I mean is that they will have to take a sample of your cancer cells, sequence them INDIVIDUALLY .. then figure out what drugs to give you in combination so that all the cancer cells can be destroyed with no chance of resistant mutations survival. In some cases this could mean developing monoclonal antibodies or small molecules tailored only to an individual target or even larger molecules tailored to multiple targets and/or ones hat can collude/coorperate.
There will need to be a mechanism in place for allowing this treatment (require virtual toxicology profiling? Require some animal test? Require the dosage to bbe given in very small amounts first (dangerous & could result in sequential resistance mutations .. that will defeat the combination therapy and make the cancer highly resistant)
I currently work with mass spectrometry to study differences in protein expression levels to understand cancer. By using the Orbitrap, we are able to study proteins in femtomolar levels and we are still far from detecting biomarkers. In deed, the field of proteomics recognizes that such is still an open chalenge, even when analyzing simple cell cultures instead of complex biofluids such as plasma. The field has become tired of published manuscripts of biomarkers that have proven wrong and are an artifact of overfiting statistical approaches. In this regard, it could be misleading to "advertise" and article as such before proving the claims on large populations.
after this much study and dedication to his profession is that "Wang cares".
Just don't say it too quickly.
My ism, it's full of beliefs.
Now if we could only program the nanotechnology to attack the cancer cells then lay dormant until the day comes that
the replicators have sent out the emergency activation beacon, which it would then restart and take control of the body, then we.....
um.....I think i watch too much stargate