Baseline Trends

It was hoped that the “decoding” of the human genome would rapidly lead to a deeper understanding of (and more targeted treatments for) a host of diseases. “Decoding” was probably the wrong choice of words, since tapping out the 3 billion nucleotide “letters” of the human genome is hardly synonymous with understanding the genome and understanding the context, both biological and environmental, in which our genomes go about their daily lives.

One of the biggest challenges in putting genetic information into context will be to understand the range of environmental factors that influence the expression of nearly all of those genes. The hope is that if individuals know they are at risk for particular diseases, say diabetes, heart disease or even cancer, this will empower and motivate them to eat right, exercise and do all the healthy things they should be doing anyway, but often don’t. It’s a bit like being scared straight. But whether genetic test information will truly be a motivator of behavioral change is an open question.

A simple example might be the common cold. We are all exposed to the viruses that cause colds. Let’s say that a small percentage of us, however, are genetically predisposed to catching a cold more easily than others. Knowing this about yourself would enable you to avoid crowded public places or at least take extra care to wash your hands, avoid sneezers and coughers, and otherwise adapt in order to mitigate the impact of your genetic constitution.

We know that each of us is unique in subtle ways, right down to the 3 billion nucleotide letters in our genomes. In those subtle differences is the great promise of personalized medicine. With heart disease, for example, doctors can easily make the diagnosis in patients once they have symptoms. But doctors can’t so easily identify all of the root causes for the heart disease. Which is why most patients will receive basically the same treatment regardless of the underlying causes.

A recent technological advance called the “gene chip” or microarray could change that. A microarray allows many different genes to be analyzed at the same time, which in turns offers great potential for solving complex multi-gene diseases such as cancer or cardiovascular disease. Microarray technology could potentially reveal the specific genetic factors that are involved for each particular patient. People with a specific mutation could then (at least hypothetically) receive treatment that is targeted precisely to them. The same technology could also help provide patients with targeted preventive treatment even before symptoms become apparent. LESS

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We are getting very good at spotting cancer at its earliest stages; screening for breast cancer and cervical cancer has helped lower mortality rates for those diseases by 30% and 60%. But in some ways, we may be getting too good diagnosing cancer. There are some experts who worry that if diagnosticians looked hard enough, they could find some sort of cancer in nearly all of us. Of men who get routine screening for prostate cancer, for example, 1 out of 6 are eventually diagnosed with cancer and most are treated with surgery or radiation. The problem is that the majority of men diagnosed with prostate would not die from it even if it was left untreated, and yet treatment often has side effects.

It’s an example of what many experts feel is a growing overdiagnosis of some cancers. Thyroid cancer, which is referred to in public-awareness campaigns as “the fasting-increasing cancer in the U.S.” is another example. According to some experts, most of us will develop thyroid cancer if we live long enough (just as most men will eventually develop prostate cancer), but very few will die from it (heart disease or something else will claim us first).

Public awareness of screening and early detection are changing the way we view cancer. It is becoming ever more difficult to not look for cancer when we have the tools to do so. Those tools include higher-resolution CT imaging, which exposes patients to higher radiation levels as well. With high-res scans, suspicious nodules are showing up in ever-greater numbers, especially in scans of lungs and colons. Once these tiny abnormalities are discovered, it is becoming ever more difficult to not do something about them. Further tests, biopsies and treatment all carry risk. The question becomes: are we lowering risk overall or raising it? LESS

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In addition to having our blood and urine tested, we might have our hair, saliva, skin, semen and even sweat also sampled. That might seem to exhaust the possibilities. In fact, though, researchers are trying to find other innovative ways to assess our health. For the past decade or two, for example, researchers have been trying to push the boundaries of breathalyzers. The instruments these researchers are devising go far beyond the devices used by cops and state troopers to determine whether someone is driving under the influence.

A person’s breath is potentially rich in information, and not just about what that individual drank or ate in the previous hours. Current methods of detecting chemicals in human breath require elaborate laboratory equipment, however, such as gas chromatographs that would not be practical for clinical situations. What would be ideal would be compact (and even portable) medical breathalyzer that could diagnose, say, prediabetes, on the spot.

Such a diagnostic breathalyzer would have to combine an impressive amount of science and technology. We tend to underestimate the power of olfaction because we consider it from our human perspective. Our sense of smell pales in comparison to a dog, whose olfactory powers are much sharper than ours. But even bloodhounds are put to shame by some moths that can detect pheromones in the air at unimaginable dilutions, the equivalent of a spritz of perfume dispersed over 10 square miles of countryside. LESS

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