One of the reasons cancer therapy is effective is that conventional drugs are somewhat indiscriminate toxins. Thus, they kill lots of tumor cells, even if those cells are not similar in their molecular properties. This is a good thing since most tumor masses are thought to be heterogeneous at the cell and molecular levels.

The bad news is that indiscriminate toxins can also damage normal tissues. Hence, the agony of awful side effects that accompanies cancer treatment.

A new study (with 30 authors from several research centers in Canada and Britain) describes an incredibly detailed look at how a single tumor—metastatic breast cancer—acquires genetic heterogeneity over time (Nature 461 [8 October 2009], 809–813).

Starting from the initial diagnosis, the research team measured genetic changes over nine years that eventually led to spread of the cancer to other body sites.

The result? Significant molecular evolution occurs as a tumor grows and then spreads. This is the source for tumor cell heterogeneity and ultimately is why some cancer cells will be eradicated by therapy and others not.

It is also a real challenge to personalized medicine to create drugs that will target every variant cell type rather than indiscriminately carpet-bombing them all. Luckily, this new work is a starting point for doing just that.

Like most contemporary people, I am a voracious consumer of information.  I readily concede that possession of information does not ensure wisdom, but at least it raises the possibility of a more informed judgment about the state of the world.

Leaving aside television and the Internet (and who wouldn’t be better off leaving these aside?), my main info sources are podcasts and books. Here are a few current favorites from each category.

My iPod is a constant companion on early-morning runs in whatever city I happen to find myself. Favored  science-related podcasts:

1. Distillations, CHF’s own award-winning romp through the world of the molecular.
2. Science Friday,the always perceptive Ira Flatow hosts NPR’s weekly broadcast on all things scientific. Unpredictable but reliably interesting content.
3. Scientific American, hosted by the always curious Steve Mirsky.
4. This Week in Science, a humorous and irreverent look at current science.

Books come in two familiar flavors: digital and analog. On the digital side, my travelling buddy Kindle currently holds three science books:

1. Science Matters (Robert Hazen and James Trefil), short and snappy essays on each major branch of science and its major questions. Easy reading.
2. What’s Next (Max Brockman), a more challenging set of 18 pieces by scientists peering into the future.
3. The Invention of Air  (Steven Johnson), a biography of Joseph Priestley focusing on the intersections of his scientific, political, and spiritual dimensions.

On the bedside table are two volumes:

1. The Age of Wonder (Richard Holmes), a totally charming history of literary and scientific explorations (some by the same people) at the cusp of the 18th and 19th centuries. Highly recommended, and the author will be visiting CHF next spring for a public lecture.
2. Cosmic Imagery: Key Images in the History of Science (John D. Barrow), a sumptuous visual exploration of how images help us make sense of the physical world. Hint: anticipates forthcoming exhibits in the Museum at CHF.

Of course, I also read unchallenging, lowbrow, and unredeeming works, mostly in the fiction category. Probity prevents me from revealing any titles….

You probably never considered the possibility that tiny bacteria have active sex lives. Rest assured they do, at least if you think the exchange of genetic information from one to another to be akin to a sex life.

But why should you care what these microscopic creatures do in the privacy of their own … wherever?

Because the DNA they exchange by a Kama Sutra-like variety of mechanisms can contain genes encoding drug resistance. And if a harmless bug transfers drug resistance to a nasty pathogen, look out, because it just might have abolished your chances of effective therapy.

If things weren’t already grim enough, consider a new report from Harvard Medical School.  Sommer et al. asked how much antibiotic resistance potential lurked in the harmless bacteria that inhabit our bodies, potentially available to be donated to disease-causing critters (Science 325: 5944 [28 August 2009], 1128–1131). The answer: an “immense diversity of resistance genes in the human microbiome could contribute to the further resistance in human pathogens.”

Even worse, many of these genes code for resistance mechanisms not yet identified. The only silver lining is that medicinal chemists can count on steady gainful employment as they labor to come up with new drugs that replace the ones rendered inactive.

If antimicrobial drug resistance really turns you on (or scares the heck out of you), I’ve written about it before (see posts from 31 July 2008 and 16 April 2009).

People have always yearned to peer at that which can’t be seen. Hence, telescopes to see into the distance and microscopes to magnify the tiny.

The resolving power for any such instrument depends of the wavelength of light used for detection and the ingenuity of the optical device used to capture that light. The human eye, as an example, is highly ingenious but limited to the visible wavelengths, thus restricting our ability to directly inspect small objects.

Electron microscopes use smaller wavelengths and can thus see smaller objects. But nobody thought we could ever see the individual atoms and bonds of a molecule because the necessary light would be so energetic as to destroy the very molecule under observation.

Luckily, intractable problems attract smart scientists. A group from IBM Research in Zurich and the Debye Institute in the Netherlands avoided the optical problem by touching the molecule instead of looking at it (Science 325: 5944 [28 August 2009], 1110–1114).

The new work uses atomic-force microscopy to visualize the complete chemical structure of pentacene, a five-ring aromatic hydrocarbon. The trick in this accomplishment lies in refining the tip of the AFM device (in this case with adsorbed carbon monoxide) so that it doesn’t perturb the sample and allows highly precise visualization. The technical achievement is dramatic enough, but the experience of actually “seeing” a real molecule is truly cosmic.

Check it out yourself, and be prepared for the most remarkable reality show possible. The wholly authentic images will send a chill down your spine.