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Sunday, Nov 8, 2009
Things like quantum-dot bar codes and magic bullets made of gold nanoshells are in the lab right now. But these therapies are not pure nanotechnology. Rather, they are a hybrid of nanotech, biotech and conventional chemotherapy. For true believers, the real revolution will come when scientists start building molecular devices from their component atoms. The wildest dreams of nanomedicine are displayed in the Nanomedicine Art Gallery, where you can view illustrations and animations of futuristic phenomena including bronchial airbots, bacterium zappers, blood probes and microbivores. According to the artist, the microbivore is "a theoretical nanorobot" that will cruise our bodies in the relentless pursuit of bad actors. If we can program these bots to eat bacteria, we can program them to eat cancer cells: So microbivores will quickly morph into the sheriffs of the nano-West, clearing out evildoers and varmints of all stripes.
Not everyone believes that molecular assemblers will be viable. But with or without them, it's undeniable that revolutionary nanomedicine-based tools are on the way. And when they arrive, they'll turn our world upside down -- and not always in a good way.
Nanomedicine will be one of the greatest boons in human history. It could eventually allow doctors to save millions of lives and prevent entire populations from contracting various diseases. But it could also push the cruel divide in medical access that already exists to the absolute limit. Those with access to nanomedicine will face a different cruel divide, created by the inevitable time lag between the availability of diagnostic tools and efficacious cures. This gap, perhaps a decade or more, will raise its own set of unprecedented ethical questions -- ones that will get even thornier once those cures are available. In the near future this tsunami of nanomedical choices could literally drown our healthcare and insurance systems.
Some of these choices involve elective genetic selection. If we can find and reprogram cancer or diabetes genes, we can certainly find and reprogram genes for simple physical traits like height or eye color. Genetic engineering raised these questions, but nanomedicine ensures they are here to stay. The physiological genetics of more complex traits like personality, sexual orientation and antisocial behavior will not be far behind. Likewise, nanobots that circulate and release chemicals on cue need not be limited to medicinal applications. (Think of the fate of the liquor industry when ethanol-releasing bots are online.) The ethical and financial implications of these developments are obvious.
But long before we have cures, nanomedicine-based diagnostics will create its own vortex of urgent healthcare issues. In the less distant future, say 2012, single-molecule DNA sequencing will mean that your genome will become an integral part of your medical record along with all sorts of other biomolecular identifiers. Beyond DNA sequencing, the tools of nanobiotechnology will allow us to predict both the metabolic state and the ultimate fate of cells and tissues with increasing precision. As a result, medicine will enter a phase we might call "Cassandra and the bell curve" -- an uneasy situation in which we can predict the future, but only partially, with the result that we never get a truly specific prophesy to believe in.
On a long enough timeline, this means a new arsenal of weapons for, among other things, the war on cancer. It will be the promised golden age of biopharmaceuticals. But meanwhile the smart money is in diagnostics.
Lots of companies are eager to get in on the ground floor. In 2000 Celera Genomics made history as the private company that forced an international consortium of developed nations to share the glory of sequencing the human genome. Celera still markets the intellectual property created by this accomplishment, but the heavyweight champion of DNA sequencing is now vigorously pursuing a career in the ring of molecular diagnostics. Celera Diagnostics is focusing its discovery efforts on "identifying genetic variations associated with common, complex diseases." And it is "working to develop new diagnostic products and to improve human health through an approach we call Targeted Medicine."
In theory, targeted medicine (aka personalized medicine) sounds awesome, and whenever it's viable most of us will want it. But before it is perfected, it will leave all of us -- patients, doctors, governments, healthcare providers and insurance companies -- in a frustrating, confusing and sometimes tragic limbo. And even after it is viable, it will raise huge questions, ones for which there are no easy answers.
Consider recent progress in the molecular diagnostics of breast cancer. Breast cancer patients with the same stage of disease can have markedly different treatment responses. In practical terms this means that no woman with breast cancer, even from the same demographic, has exactly the same illness as any other. Each woman's cancer has its own unique genotype. Currently, conventional medical treatment with chemotherapy can reduce the risk of metastases by approximately one-third. However, clinical data also show that 70-80 percent of patients receiving chemotherapy do not, in fact, benefit from it. Put simply, at least seven out of every 10 women patients endure chemotherapy for nothing. The agonizing current dilemma for doctors and patients is that chemotherapy will prolong life for three of the 10 women, but we can't determine which three.
The plan is to use gene-scan data to predict which patients will benefit from chemo. In 2002, workers in the Netherlands used a DNA microarray to develop a gene expression profile that outperformed all currently used clinical parameters in predicting disease outcome. They suggested that their findings provided a strategy to select patients who would benefit from adjuvant therapy (i.e. chemotherapy and/or radiation). This information, originally published as basic research, reached the public in articles with encouraging titles like "New Study Could Cut Breast Cancer Overtreatment." In this article, a member of the research team was quoted as saying, "We have confirmed that we can predict with 90 percent certainty that a patient will remain free of breast cancer for at least five years." Since then things have improved, but only incrementally.
