Depression increases deaths from cancer

Elizabeth Blackburn.
Elizabeth Blackburn. / V. Carrasco
  • Nobel Prize winner Elizabeth Blackburn says that measuring the ends of the chromosome can predict future illnesses

Scientist Elizabeth Blackburn, current president of the Salk Institute of Biological Studies of California, discovered 'telomerase', an enzyme found at the end of the chromosomes, in what is known as the 'telomere'. This finding won her the Nobel Prize for Medicine in 2009, together with Carol Greider.

"A telomere is the cap of the chromosome, like the end of a shoelace, comprised of protective cells - nucleotides - which stops them unrolling or sticking to others," said Blackburn during her recent lecture 'Paradoxes in the biology of telomeres and cancer' which took place in Madrid, "and we found an enzyme called 'telomerase' in the 'telomeres', which has the ability to repair them."

Different lines of research have been carried out from that discovery, and they have determined that this lengthening or shortening of the point of the chromosome is related with illnesses such as cancer. As they shorten with age, along a line which starts to descend when people are in their 20s and reaches a valley in the 70s, repairing the telomeres could cure some age-related problems.

Depression and cancer

"We know there are hundreds of different types of cancer and around 90 per cent of them, at an advanced stage, show great activity in the telomerase. This suggests that if the enzyme can be inhibited, the cancer might be able to be cured," said Elizabeth, who was born in Australia in 1948 but spent many years in the US, where she developed her scientific career.

She is, however, quick to sound a note of caution. "There are currently clinical tests at an initial stage which indicate that this would be difficult to achieve because the stem cells in our body, the ones that send information to the rest of the cells, need natural telomerase to function. That means that if we were to inhibit the cancer cells, it could also affect the stem cells as well," she explains.

One recent piece of research, which this scientist cites as a specific example of the application of her finding, showed that suffering from depression, combined with little length in the telomeres, increases the mortality rate from some cancers.

"A study at the Cancer Centre of Texas measured the telomeres and the degree of depression in 440 patients who had recently been diagnosed with cancer of the bladder," said Elizabeth.

"The results showed that the patients with short telomeres who were not depressed survived on average for 200 months, just like those with long telomeres, whether or not they had depression. However, the group that combined depression and short telomeres had a higher mortality rate and survived for 30 months. That's a huge difference. The telomeres can predict mortality."

With regard to the relationship between mood and length of telomeres, she points out that other studies have shown that stress shortens the telomeres, making the individual more susceptible to developing some types of cancer, diabetes, cardiovascular and lung conditions, arthritis and dementia.

"Adults who suffered great violence as children have shorter telomeres now," she explained. "Exposure to traumatic events is associated with this shortening and, therefore, greater possibilities of suffering from illnesses. Even stress during pregnancy can have an effect on the length of the child's telomeres, as can cases of abuse and unsafe environments."