Saturday, October 25, 2014

The Cancer Chronicles - George Johnson's personal exploration of cancer, its origins, and treatments

I have recently reviewed books about the discovery and treatment (The Philadelphia Chromosome) and the causes of cancer (Toms River). So the subject matter in George Johnson's The Cancer Chronicles is quite familiar to me. Johnson does have a unique angle – his wife was diagnosed with uterine cancer, which led him to use his expertise as a science writer to learn more about the disease. This perspective helps create a personal element to the book, but does not distract from the science.

Several of the stories were previously covered in other books that I have reviewed: Boveri's prescient hypothesis linking chromosomal aberrations with cancer (The Philadelphia Chromosome), Thomas Hunt Morgan's mutant fruit flies (The Violinist's Thumb), scrotal cancer in chimney sweeps (Toms River), and the Radium girls (The Poisoner's Handbook). Johnson covers new ground in the chapter called "Jurassic Cancer", which examines the other animals in which cancers have been found. In fact, most animals get cancer; the one exception is naked mole rats. Surprisingly, various types of malignancies have even been identified in dinosaur fossils. Another chapter examines how far back in human populations cancers have been described. Johnson writes, "There were signs of cancer in an Iron Age man in Switzerland and a fifth century Visigoth from Spain" (p 49). In both animals and humans, it is difficult to know the exact frequency of the disease, but it is clear that cancer is not strictly linked to industrialization or environmental factors. 

Hanahan and Weinberg, 2000.
Rather, it seems that cancer is inevitable. The landmark review "The Hallmarks of Cancer" (and its update in 2011) states that cancer is basically caused by the accumulation of several mutations. The review's author Robert Weinberg estimates that every second four million cells are replicating in a human body. Each time a cell replicates, there is a chance for error. While there are many error correction mechanisms, mistakes do get through. This genetic variability is the fodder for evolution by natural selection. It is also the source for cancer. Thus, it makes sense that cancer is generally seen throughout the animal kingdom and throughout time. Johnson concludes that it is comforting to know that cancer has always been with us.

Johnson also discusses cancer cell evolution, which is a topic of intense interest in scientific research. Cancer cells are constantly changing to evade the body's defense mechanisms. During treatment, some cancer cells can develop resistance to chemotherapeutics. Understanding how chemoresistant cancers can be treated is a major unanswered question. In the case of Gleevec/imatinib-resistant cancer, a single mutation is responsible for Gleevec-resistance, which allowed the development of a second drug (nilotinib) to kill cells with the imatinib-resistant mutation. Unfortunately, and as is to be expected with a complex disease such as cancer, most chemo-resistant cancers are not as clear cut. 

Overall, the book is quite easy to read and covers many important topics, albeit not at the depth of other, more focused books on the topic of cancer. I will definitely be adding The Emperor of All Maladies to my reading list to give this topic another perspective.

** Post script: Johnson's book was short-listed for the 2014 Royal Society Winton Prize for Science books. 

Saturday, October 4, 2014

The Tale of the Dueling Neurosurgeons - more weird science from Sam Kean

I normally don't get very excited for a book release because I always seem to have lots of books on my reading list. Since I enjoyed the previous books from Sam Kean (The Disappearing Spoon and The Violinist's Thumb) so much, I actually set my calendar to remind me about the release of The Tale of the Dueling Neurosurgeons. I don't know much about neuroscience, so I knew that Kean would teach me something new. As usual, Kean finds the most fascinating stories to keep you in awe of how the brain works and highlight the numerous ways in which the brain can malfunction.

Phineas Gage and his tamping rod

The theme of the book is that neuroscience is unique in that most of the early lessons about the function of the brain came from observing the behavior of people with damage to a particular region of the brain. This is still the case; a recent story about a young woman without a cerebellum demonstrates the plasticity of the brain and its ability to compensate for problems in even the most seemingly critical parts. The book includes lots of case studies and stories of strange behavior. The final chapter presents the tale of Phineas Gage, who is a bit of a legend in the field of  neuroscience. Sam Kean wrote a piece for Slate about Phineas Gage; I recommend reading it if you want to get a quick idea of whether or not you will like the Dueling Neurosurgeons.

Perhaps the most fascinating tidbit concerned Teddy Roosevelt and his treatment by neurologist Silas Weir Mitchell, whose "West cure" for men included a variety of rugged outdoor pursuits. Before seeking the cure in the 1880s, Roosevelt had been compared to Oscar Wilde for his effeminate voice and foppish mannerisms. As you would expect for the time, Mitchell's cure for women was very different; women suffering from "hysteria" were prescribed long term, isolated bed rest with massages and fatty foods. Many women suffered through this treatment, including Virginia Woolf. (You can read more about the gender-biased treatments of Silas Mitchell here.) Silas Mitchell built his reputation on his work in the area of phantom limb, the phenomenon where an amputee may feel an itch or pain in the limb that has been removed. Radiolab had an excellent story on this topic, which covered the innovative but simple approaches used to treat this strange problem. 

When you hear about people who taste colors or see smells, they are typically exhibiting synesthesia. The most common forms of synesthesia are people who see sounds in certain colors or hear sounds in connection with particular letters or numbers. Physicist Richard Feynman and author Vladimir Nabokov both experienced these sensory combinations (the internet tells me that Lady Gaga was also born this way). The reason that these particular combinations are more common is likely due to brain geography: the regions that analyze sounds, colors, and letters are close together. Interestingly, sixty different types of synesthesia exist, but it is not completely clear what causes this jumbled wiring. It is becoming clear that this commingling of the senses could be a benefit. Some synesthetes have an excellent memory, which they attribute to their unusual perception of the five senses. This correlation suggests that training your brain to link colors and letters, for example, could improve cognitive function. Some synesthetes have links between their sense of smell or taste and the other senses. This causes them to experience sounds or colors associated with some flavors. As you could imagine, this might expand their palate, as described in this NPR story about the benefits of being a synesthete in the food and beverage industry.

Dueling Neurosurgeons was another excellent outing for Sam Kean, who continues to amaze me with stories of weird science. I also loved the rebus puzzles that Kean added at the start of each chapter. Like the DNA acrostic in The Violinist's Thumb, Kean has found a novel way to engage his readers.