In 2013 alone, cancer plagued nearly 14.5 million people, creating an ever-growing desire to find the causes behind this deadly disease. And today, for the first time, scientists have discovered that random chance may have the largest impact on your risk of getting cancer.
According to a recent study, scientists estimated the percentage of cancer mutations due to hereditary factors, environmental and lifestyle factors, and happenstance. They found that 66 percent of the genetic mutations that develop into cancer are caused by simple random cellular errors that occur when cells replace themselves.
In comparison, 29 percent of mutations are a result of environmental factors, while the remaining 5 percent are inherited, assert Cristian Tomasetti and Dr. Bert Vogelstein, both of Johns Hopkins University.
This is a significant paradigm shift from the 1960s and 70s, when it was commonly believed that the majority of cancers were caused by behavioral and environmental factors, with inherited factors coming in last place.
"Every time a perfectly normal cell divides, as you all know, it makes several mistakes--mutations," said Vogelstein in a briefing. "Now most of the time, these mutations don't do any harm. They occur in junk DNA, genes unrelated to cancer, unimportant places with respect to cancer. That's the usual situation and that's good luck."
But unfortunately, some cell mutations occur in cancer-prone genes--what Vogelstein accurately describes as "bad luck."
In a previous research paper published in 2015, Tomasetti and Vogelstein used a mathematical model to propose the idea that your cancer risk is related to the number of divisions your cells undergo. By comparing this number to cancer case figures in the United States, they found a strong correlation between cell divisions and lifetime risk of acquiring each of the 31 types of cancer they tested.
Their latest study built upon this research--studying the correlation between cell divisions and cancer risk of 4.8 billion people (or two-thirds of the world's population) across 17 different types of cancer. Although they discovered that more than half of cancer mutations resulted from random chance, Tomasetti and Vogelstein assert that lifestyle and environmental factors still play a huge role in cancer proclivity.
Obesity, lack of exercise, and poor eating are thought to supply the necessary third gene defect that creates a disease state like cancer--a result of multiple cell mutations.
Cigarette smoking is also linked to more genetic mutations--which can result in cancer or non-cancer-related genes. Although chance does come into play here, one thing is certain: our bad habits, which we completely control, can make or break our longterm health.
So while this new study is certainly an eye-opener, don't fret: There's still lots you can do to decrease your risk of cancer.