Thursday, January 28, 2010

Infrequent fliers and cancer

Fun with correlational studies: How often should you fly in order to minimize your risk of developing cancer? Clearly flying very frequently is not a good idea since the risk of certain cancers is increased in airline flight crew. This makes perfect sense since airplanes fly at high altitude where there is greater exposure to cosmic radiation, and we all know that radiation exposure increases your risk of developing cancer.
There is, however a contradictory correlation, that people living at higher altitudes experience lower rates of cancer. This was a surprising finding which led to the hypothesis that the thinner air at higher altitudes offered some protection, perhaps having something to do with oxygen free radicals. This seems unlikely to me since, at altitudes that people inhabit there is no change in air composition with altitude. The air is thinner but the relative amount of oxygen does not change. Since we know that intermediate radiation doses can be protective for certain cancers, would it not make sense that the higher doses of radiation at higher altitudes be protective?
I suggest that a devious airline (with no respect for privacy) and an American health insurance company (which has little respect for anything but money) join forces and use frequent flier miles and see if there is an amount of flying that protects against some types of cancer.


Thursday, January 21, 2010

Things they don't tell you in school

"We do not need more scientists, but academic science as practiced depends on a large surplus of expendable trainees (grad students and postdocs) who have to believe that a career in research is an attainable goal. This creates an overtrained, underemployed workforce, but the alternative is to make "trainee" type research positions professional positions, which would be expensive. First, because you would have to offer real salaries and benefits, and second you could not create the illusion that working 80 hour weeks for 40,000 a year is going to someday get you your own lab, meaning less work out of each employee."
From a comment here via this post


Tuesday, January 19, 2010

Dental Cancer

An interesting conversation on the weekend somehow made its way to teeth and whether there were particular kinds of oral cancer specific to the tooth. Maybe our dentist readers can fill in some knowledge gaps here.

Tooth enamel has no living cells and so, unlike bone, cannot repair itself or become cancerous. However, the tooth does have living cells in the dental pulp, so perhaps they may be susceptible to transformation and uncontrolled growth. Clearly the easy answer would be to consult Pubmed. An even easier solution is finding the one paper that already did that for you, in this case a paper in The Lancet Oncology entitled Teeth: malignant neoplasms in the dental pulp? From the abstract:
[U]sing the search phrase “dental pulp” combined with “sarcoma”, “carcinoma”, or “neoplasms” in PubMed when using the MeSH search mode yielded no reports on primary malignant neoplasms. However, a hand search yields clinical reports on pulpal tumours that were published over a century ago.
OK, so tooth tumours do happen - or did over a century ago. Why aren't there any today? Water fluoridation? The authors offer some thoughts about that:
Because of the restricted space in a tooth, tumour expansion will probably lead to the formation of irritation dentine by secondary odontoblasts and, subsequently, to a haemorrhage infarct of the pulp. One hypothesis states that a purported neoplasm of the dental pulp leads to a chronic appositive pulpitis and–sooner or later–will be treated likewise by root-canal treatment or extraction.
So dental cancers may be happening with some frequency but manifesting and being treated as other conditions. Or maybe the dentists really know what's going on and would rather pocket the treatment fees themselves rather than referring patients for radiation and chemo. They are, after all, in the pocket of Big Floss.


Monday, January 18, 2010

Cancer Carnival: Call for Posts

The 30th edition of the Cancer Research Blog Carnival is coming up in a couple of weeks. We have a great host, Health and Life lined up, where it will appear on Friday, February 5th. That's plenty of time to write something new, or submit a recent cancer-related post. Submissions can be made on this form.


Wednesday, January 13, 2010

Open Lab 2009

The Open Laboratory 2009 is an anthology of 50 blog posts selected and judged as the best science blogging of the year. This year saw 760 entries, and for the second year in a row I'm proud to have one of my posts, Good Head, deemed worthy for inclusion. The final list of posts can be found here. Many thanks to editor SciCurious, Bora Zivkovic and all of the judges!


Tuesday, January 12, 2010

Slug acquires photosynthetic genes

Evolution will never cease to amaze me: scientists have found a slug who can make its own chlorophyll!

"Shaped like a leaf itself, the slug Elysia chlorotica already has a reputation for kidnapping the photosynthesizing organelles and some genes from algae. Now it turns out that the slug has acquired enough stolen goods to make an entire plant chemical-making pathway work inside an animal body, says Sidney K. Pierce of the University of South Florida in Tampa.

The slugs can manufacture the most common form of chlorophyll, the green pigment in plants that captures energy from sunlight, Pierce reported January 7 at the annual meeting of the Society for Integrative and Comparative Biology. Pierce used a radioactive tracer to show that the slugs were making the pigment, called chlorophyll a, themselves and not simply relying on chlorophyll reserves stolen from the algae the slugs dine on."


CCRG doctor finally busted

Those of you who have followed the saga of foul-mouthed, vitamin-peddling quack extraordinaire "Dr Hope" who runs the "Canadian Cancer Research Group" which despite the name has yet to show any proof that their expensive miracle alternative treatment has any benefit to cancer patients, will find solace in the recent news that the only doctor working at that "clinic" will most likely have his license suspended:

"According to the document released Wednesday, O'Shea is also accused of failing to properly gain consent from patients, failing to examine patients before prescribing treatment or medication and failing to communicate with patients' primary health care providers.

O'Shea is scheduled to appear at the College of Physicians and Surgeons' Toronto headquarters Jan. 26. If he is found to have violated professional standards, O'Shea could lose his license to practise medicine and face a fine of up to $35,000."

Now only Bill remains to be taken down, and we know the competition bureau is on the case, but it is much harder since he is not a physician. Too bad he is quick to threaten everyone with lawsuits yet wont defend himself by returning calls from the Ottawa Citizen...


Off with their Heads!

I've written before about a possible beneficial side effect to circumcision - the reduction in HIV infection risk.

In an effort to identify other changes in circumcised penises (other than the obvious), and to drum up business for the local mohel, scientists have examined differences in the penis microbiome in a recent paper published in PLoS ONE. They conclude:
The anoxic microenvironment of the subpreputial space may support pro-inflammatory anaerobes that can activate Langerhans cells to present HIV to CD4 cells in draining lymph nodes. Thus, the reduction in putative anaerobic bacteria after circumcision may play a role in protection from HIV and other sexually transmitted diseases.
While the main thrust of the paper is the reason for the previously mentioned HIV risk reduction, there are some other interesting outcomes for the reduced numbers of an anoxic environment and the corresponding bacteria. Mike the Mad Biologist has more:
This seems to be a much more compelling finding: circumcision might reduce bacterial vaginosis. While bacterial vaginosis isn't dangerous except in very limited circumstances, it still is a nuisance. To me, that's the compelling finding, although vaginas probably make news editors giggle, so that's probably why vaginosis wasn't covered.
Somehow I still don't think people will be queueing up...


Friday, January 08, 2010

An Inconvenient Sponsor?

GlaxoSmithKline is going to finance a documentary about obesity. A good documentary on obesity is probably overdue and has the potential to be very interesting to me. An article in the New York Times has some more details about the movie and the controversy around Glaxo as a financial backer and the potential for this documentary to be a disguised infomercial for Alli, Glaxos over the counter weight loss drug. You may know alli from it's famous side-effects. Excreting dietary fat can get ugly.
The comparisons to An Inconvenient Truth from the NYT article are interesting since obese people serve an important role as a carbon sink.


Saturday, January 02, 2010

Darwinian Evolution of Prions

Here is an original article describing the phenomenon of prion evolution in Science magazine. It would seem that this is the first example of evolution that is distinct from genetics. I haven't read the article in detail but cjdblogger has a decent summary.


Friday, January 01, 2010

Cancer Carnival #29

Happy New Year, and welcome to the first Cancer Research Blog Carnival of 2010. It will be a light one - the holiday season kept us all busy - but there's still some good stuff to be had. We also have some new hosts lined up in the new year starting next month at Health and Life.

In fact, we'll kick things off with a post from that blog, comparing Tamoxifen to Arimidex as adjuvant therapy for cancer.
There has been a lot of debate about how to prevent cancer from coming back in post-menopausal women after initial treatment. We discussed in our comparison of Tamoxifen with aromatase inhibitors the debate in general, and now will analyze Tamoxifen vs Anastrozole, brand name Arimidex, directly.
The author, David, does a nice job of summarizing various studies comparing the two drugs. The blog itself features a large amount of cancer blogging, much of it from a pharmacological point of view and looks to be a nice resource for health information in general, and drug uses and side effects specifically.

Next up GeriPal responds to news stories that morphine and other opiates may promote cancer growth and spread with some research blogging
This is an interesting line of research and one that gave the makers of Relistor a shot in the arm (as one website put it – “a possible new indication for Progenix's Relistor could revive its fortunes”.) I find the pathophysiology behind this incredibly interesting from an academic standpoint, however it is neither something that would warrant such dramatic headlines nor spur thoughts that it is anything but research in its infancy.
As usual, the headlines don't tell the full story, but GeriPal has it, so click through to find out the real deal.

Something we don't often think about while focussing on human disease is cancer in animals. PetPip reminds us that pets get cancer too, and how to cope.

Speaking of animals with cancer, one favourite from past carnivals has been the transmissible tumours among tasmanian devils. A recent paper in Science has determined the origins of these tumours, as Carl Zimmer describes in the New York Times
When the tumor disease was discovered, many scientists assumed that it was caused by a rapidly spreading virus. Viruses cause 15 percent of all cancers in humans and are also widespread in animals.

But subsequent studies failed to turn up a virus. Instead, Anne-Maree Pearse and Kate Swift, of the Department of Primary Industries, Water and Environment in Tasmania, discovered something strange about the tumor cells. The chromosomes looked less like those in the animal’s normal cells and more like those in the tumors growing in other Tasmanian devils.
The full story is pretty fascinating, and worth the read. Razib Khan at Gene Expression adds a bit more, commenting on the dire predictions for the devil's demise and pointing out that some animals are, in fact, immune.

That's it for this month's Cancer Research Blog Carnival. For older editions, visit the Carnival Homepage. Don't forget, the CRBC has subscription options; you can follow by email or RSS feed. An aggregated feed of credible, rotating health and medicine blog carnivals is also available.