Wednesday, October 20, 2010

Cancer is (NOT) a modern, man-made disease

Last week, what started as a press release by the University of Manchester to publicize an opinion article by its faculty, and picked up by some ‘reputable' media (like Telegraph), led to a tsunami of rebuttals and jabs all over the blogosphere.

University of Manchester’s press release “Cancer is a modern, man-made disease caused by environmental factors such as pollution and diet, a study by University of Manchester scientists has strongly suggestedsummarizing Rosalie David & Michael R. Zimmerman’s article “Cancer: an old disease, a new disease or something in between?”  which was published in October issue of Nature Cancer Reviews, generated headlines, such as, “cancer is purely man-made,” “cancer is a modern disease,” “no cancer in ancient times.”

The study of remains and literature from ancient Egypt and Greece and earlier periods – carried out at Manchester’s KNH Centre for Biomedical Egyptology and published in Nature – includes the first histological diagnosis of cancer in an Egyptian mummy.  Finding only one case of the disease in the investigation of hundreds of Egyptian mummies, with few references to cancer in literary evidence, proves that cancer was extremely rare in antiquity. The disease rate has risen massively since the Industrial Revolution, in particular childhood cancer – proving that the rise is not simply due to people living longer. . . Read more.

The arguments on the other side (that the cancer has been around as long as humanity) are equally strong and spirited:
  1. They made inaccurate assumption that the tumor evidence on old bones were actually bone growth or lumps.
  2. Andreas G. Nerlich’s group in an age and sex-adjusted analysis did not find difference in tumor rates in an English cohort (from 1901-1905 AD), ancient Egyptian population, historical southern German and recent English more
  3. Natural causes of cancer were present then as now: UV, radon from granite rocks, viral infections (HPV, EBV, hepatitis virus), Helicobactor pylori, soot and smoke; chemicals in food, such as, aflatoxin from molds on bad peanuts or grains, phorbol esters in herbal meds.
  4. Rosalie David and Zimmerman’s analysis is from mummies and skeletons of people who did not live past 30s or 50s. 
  5. According to Cancer Research, UK, three-fourth of diagnosed cancers are in people aged 65+ and one-third in aged 75+.  Cancer rates and aging follow direct relationship and life expectancy in US has increased from ~50 in 1900 to ~75 today.
  6. We diagnose cancer better now – with better tools!
  7. **There is more to cancer mechanism than just lifestyle choices, pollution and chemicals.

Next frontier: Cancer needs a TOE (Unified Theory of Everything) like in physics!

(Fig from: Cancer Res 51:5023s (Sept 15, 1991)

In the late 70s and early 80s, Frederick F. Becker wrote (edited) “Cancer: A Comprehensive Treatise.”  Every cancer biologist at that time had seen or read this Bible which was published in several volumes, including one devoted to “Etiology: Chemical and Physical Carcinogenesis,” and another to “Etiology: Viral Carcinogenesis” and “hormones.” The common theme was that cancer development is a two-hit mechanism - the initial genetic change/error (initiation) needs a second step (promotion) via chemicals/viral/etc to evolve to cancer.  This is not very different than David and Zimmerman’s take. 

Now, add to this, the role of epigenetics, growth factors, tumor microenvironment, tumor immunology and cancer stem cells and mechanisms contributing to angiogenic switch, it  paints a picture of an ecosystem gone awry.  
This is where cancer theory needs a "toe" to hold all the silly bandz mechanisms.

Further Readings: 
  • Cancer: an old disease, a new disease or something in between? A. Rosalie David & Michael R. Zimmerman. Nature Reviews Cancer 10, 728-733 (October 2010) | PubMed | DOI | FullText
  • Blogosphere: NewScientist, Cancer Research UK, Physics Forum, Corante 
  • Paleopathologic diagnosis based on experimental mummification. Michael R. Zimmerman. American Journal of Physical Anthropology 51(2): 235-253 (1979) | Scholar | DeepBlue |  
  • Environmental and occupational causes of cancer: new evidence 2005-2007. Clapp et al. Rev Environ Health.23(1): 1–37 (2008 Jan–Mar) | PubMed | 
  • Chemical and physical carcinogenesis: advances and perspectives for the 1990s. Curtis C Harris. Cancer Res 51:5023s (Sept 15, 1991) | PubMed | Scholar | FullText

  • Cancer: A Comprehensive Treatise, Volume 1. Etiology: Chemical and Physical Carcinogenesis (reviewed in Yale J Biol Med. 1983 Mar–Apr; 56(2): 164–165. FullText | 
  • Cancer: A Comprehensive Treatise. Volume 2. Etiology: Viral Carcinogenesis (reviewed in Br J Cancer. 1976 October; 34(4): 456. FullText | 
  • Cancer: A Comprehensive Treatise. Edited by. Frederick F. Becker, Plenum Press, 1982 | Google | Scholar |

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