Cancer-Causing Mutations

An article highlighting healthy people having way more cancer-causing mutations that were originally thought, was composed by Yasemin Saplakoglu, Staff Writer for Live Science.  These mutations are caused by changes in our bodies and cells from aging.  These changes could be a lot greater than what was previously thought.

There are more mutant cells in the esophagus of middle-age and elderly people than in normal cells, according to a group of researchers as recently reported in the journal Science.  Some of these mutations are associated with esophageal cancer.

The human body is created from a set of instructions carried in every one of our cells as an individualized manual called our genes.  Throughout our lifetime it changes or mutates, which creates new instructions.

The mutations have no effect on healthy cells that continue chugging along unfazed.  Some mutations can be detrimental and a new set of instructions can tell healthy cells to divide and multiply rapidly that prevents other cells from stopping this uncontrolled cell growth.  This can cause healthy cells to turn cancerous.

The researchers wanted to understand what mutations are in healthy people, so they examined the tissue that lines the esophagus from nine donors between ages 20 and 75.  Gene sequencing, which is a method revealing the genetic makeup of a tissue, was used to see how many known cancer associated mutations each donor carried.

Their findings were that by the time people reached middle age, over half or 14 of the tissue lining the esophagus contained mutated genes that were associated with esophageal cancer.  One of the mutated genes, NOTCH1, was more common in healthy tissues than in cancerous ones.

In the middle-age and elderly participants, NOTCH1 mutants were present in 12 to 80% of cells and TP53 mutants was found in 2 to 37% of the cells.  The researchers may need to reconsider the role these genes play in cancer.  Genetic mutations associated with cancer are widespread in normal tissues, revealing how our own cells mutate, compete and evolve to colonize the tissues as we age, said co-author Inigo Martincorena, a group leader at the Wellcome Sanger Institute in the United Kingdom.  He also said it is remarkable that they have been unaware of the extent of this phenomenon until now.

Mutations are also carried in tissue other than the esophagus.  Because of the sun, a quarter of a middle age person’s skin cells have mutations that can drive cancer.

Even with shedding light on early cancer development, it also raises questions about how these mutations might contribute to aging and other diseases.  This opens interesting avenues for future research.

Dr Fredda Branyon