Because it is so horrible and seemingly random, we have always associated someone coming down with cancer as particularly “bad luck.” But new research conducted in adult human stem cells is providing us with some insight that luck has less and less to do with it.
In the “Lifestyle versus Luck” debate that has raged in oncological for the past year, the “luck” camp has subscribed to the notion that the variation in cancer risk among different organs is mainly down to a difference in the number of ‘bad luck’ DNA mutations in stem cells from these organs. They believed that organs with faster rates of stem cell division would naturally accrue more random mutations and carry a higher cancer risk.
However the researchers, working out of UMC Utrecht in the Netherlands, have found that the DNA code of human stem cells acquires errors at a fairly constant rate, even in organs with differing cancer incidence. This effectively debunks the Bad Luck theorists.
“We were surprised to find roughly the same mutation rate in stem cells from organs with different cancer incidence,” says Dr. Ruben van Boxtel, lead researcher of the team. “This suggests that simply the gradual accumulation of more and more ‘bad luck’ DNA errors over time cannot explain the difference we see in cancer incidence – at least for some cancers.”
The scientists studied stem cells isolated from colon, small intestine, and liver biopsy samples and found that DNA error accumulation in these cells did not vary. Instead, they remained extremely stable, at about 40 mutations a year.
The scientists published their results in the journal Nature.
“Some organs are more prone to developing tumors than others,” says Dr. Lara Bennett, Science Communication Manager at Worldwide Cancer Research. “For example as many as 110 new cases of bowel cancer are diagnosed every day in the UK, compared to just 15 cases of liver cancer.”
The “Bad Luck” camp is not totally out of luck, however. The researchers did find differences in the types of unavoidable stem cell DNA mutations between the tissues, which Dr. van Boxtel says could ultimately turn out to partly explain increased rates of cancer in some organs like the bowel.
“So it seems ‘bad luck’ is definitely part of the story,” he says. “But we need much more evidence to find out how, and to what extent. This is what we want to focus on next.”