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Matter of perspective or how the point of view affects research

Cancer is one of the biggest health risks both in developed and developing countries. With more than 14 million diagnosed cases and 8.2 million deaths in 2012 according to the WHO, there is a huge social pressure over the research on this illness. For many years, physicians, biologists and other scientists have been launched to find a cure for cancer, with partial success in the best cases. After several decades of studies that drive to unsuccessful clinical trials and although the most common kinds are quite more treatable than 20 years ago, some research projects are separating themselves from pure medical research in order to reach a more global point of view. That is, understanding where it comes from, and how it works, is the first step in order to find a possible reliable and general treatment for cancer, maybe even a common treatment for every type of cancer.

Illustration by Klifton Kleinmann.

This is a very important step, since funders, those who really determine which projects are carried out or not, are not that fond of basic research, as it offers unknown benefits, while looking for a cure to an illness has a very evident benefit.

Thanks to this new focus, it is quite common nowadays to find, both in specialized journals and mass media, news about new discoveries in this field. Although we must not be carried away by the enthusiasm shown by some of these articles, it is always good news when new discoveries are made on this topic.

For instance, an article by Tomasetti et al., which has been widely commented on mass media and social networks alike –not always in a rigorous fashion–, perfectly illustrates this change of focus. In summary, this team of scientists from the Sidney Kimmel Cancer Center, an institute of the John Hopkin University, have discovered that, according to their data, only a third of the total probability of developing cancer is associated with lifestyle, genetic or environmental factors. The other two thirds would be, according to this study, product of stochacticity (badly described as “bad luck”). The DNA copying process, by the way it works, have a chance of error that is common to all the cells of the body (15 bases mutated every year, on a 6.6 million bases genome). This means that tissues with higher division rates, as the liver, will have a higher probability to develop a cancer.

The entire human genome printed out as a series of books. Wellcome Collection, London. Photo by Russ London (licensed under CC BY-SA 3.0, source).

This discovery would come to knock the idea of causation of cancer. It would mean that having a cancer could possibly not be caused by your lifestyle, and that having a carcinogen-free life is not an insurance against it.

However, as the authors of the study state in their article, there are some types of cancer that are more influenced by environmental factors than others. Among them, we can find the different colon, lung and pancreas cancer; all of them impact organs with a high cell division rate. Sometimes environmental factors increase the division rate of these tissues, as in the case of the asbestos induced lung cancer, the cirrhosis related liver cancer or the chronic constipation related colorectal cancer. As exposed before, this increase in the cell division rate also increases the probability of having an error that eventually develops into a cancer. Also, other scientists have pointed to some flaws in the study: prostate or breast cancer, both among the most common types of cancer, were not included in the study (maybe since they are dependent on the patient’s sex) and that the data comes only from the USA.

If we follow the reasoning of this research, the next question would be: if cancer appearance is related to the way DNA works, where does the malfunctioning comes from?

Our second example, an article by Domazet-Loso et al., answers to this question. It describes their attempts to trace back the evolution of tumors. They centered on a basal metazoan (an animal with basic characteristics) called Hydra. This is a well-known group in zoology, and a good representative of the cnidarian, the group that includes corals, anemones and jellyfish. Until recently, naturally occurring tumors had not been found on cnidarians nor sponges, even when some statistical models had predicted so. However, this team has found tumors in at least two species of this genre.

Hydra. Photo by Przemysław Malkowski (licensed under CC BY-SA 3.0, source).

The way those tumors grow is similar to the oozytes formation (the cells that act like eggs on these animals) with the exception of the apoptosis process. This step is vital, since it’s when the inner cells of the mature oozyte (those that are still in contact with the mother’s body) die, separating the oozyte from the mother. Without this apoptosis, the tumor keeps growing occupying not only the external space, but even the internal cavity, preventing the animal’s survival and reproduction.

The researcher’s team conducted a series of experiments during which they bred some tumorous individuals. The descendants of these individuals also presented tumors, and this may suggest that tumor cells had migrated to the oozytes and then developed on the offspring. With this in mind, they tested the mobility of tumor cells. Results showed that the cells arrived everywhere on the animal, independently of where they were inoculated.

This article shows some interesting data about the origin of this illness, even suggesting that it could be an illness inherently associated with multicellularity, since even the simplest animals on this planet have these problems.

With different methodologies, objectives and even fields, both researches throw some light over topics that, from a more “practical” point of view would be overlooked, but that are really interesting in order to understand the way cancer works, its appearance, propagation and maybe treatment. With this in mind, I would like to acknowledge the value of all those researches that, not being focused on the traditional goal to "cure cancer", surely are paving the way for a real and effective solution to a disease that causes millions of deaths every year.

Bibliography

  • Tomasetti, C., & Vogelstein, B. (2015). Variation in cancer risk among tissues can be explained by the number of stem cell divisions. Science, 347(6217), 78-81.
  • Domazet-Lošo, T., Klimovich, A., Anokhin, B., Anton-Erxleben, F., Hamm, M. J., Lange, C., & Bosch, T. C. (2014). Naturally occurring tumors in the basal metazoan Hydra. Nature communications, 5.
  • World Health Organization (February 2015). Fact sheet No 297.