Cancer is the second leading cause of death globally, and is responsible for an estimated 9.6 million deaths in 2018

The World Health Organization (WHO) has found that nearly eight million annual death occur from cancer around the globe. It is horrifying to know that about 13 percent of all deaths globally are caused by cancer. That’s not all. WHO has also estimated that new cancer diagnoses will increase by 70 percent over the next two decades.

With that in mind, the question of “Is it nature or nurture?” has been a long-standing debate that spans an array of scientific disciplines. The term nature refers to the diseases in our genes, e.g. mutation. Nurture, on the other hand, refers to the lifestyle choices individuals make and the environment that shapes them.
Is it nature or nurture that increases cancer risk? You will learn in this post that there is no single cause. Be it nature, nurture, high risk genes, or high risk lifestyle, they are all interlinked.

Gene Mutation – “Nature” Factor A

The nucleus serves as the control center of the cells in your body. It is composed of 23 pairs of chromosomes, which are made up of genes. These genes act like coded messages, telling how cells should behave. Each human has approximately 25,000 genes and they tell our bodies how to grow and develop.

Unfortunately, some individuals have an inherited gene fault. This increases the risk of particular types of cancer. Cancers develop when something goes wrong with more than one gene in a cell. An unwanted change in a gene is called a mutation or fault. Oftentimes, a cell becomes cancerous when it has six or more gene faults. Once the cell becomes cancerous, it may divide and spread uncontrollably. It’s important to note that gene faults can be inherited from a parent or occur during your lifetime.

Gene faults can happen when one is exposed to carcinogens, e.g. excessive sunlight and cigarette smoke. In this case, these gene changes do not affect all body cells. They are not inherited and cannot be passed on to one’s children. In other words, they are called acquired mutations. Cancers that occur from these mutations are called sporadic cancers.

Cancers that are caused by inherited faulty genes are less common than those caused by gene changes due to aging. As mentioned, cancers are not caused by inheriting a specific cancer gene. It is a combination of one’s environment (nurture) and chance (nature).

Family History – “Nature” Factor B

One has a strong family history if one or more situations below apply to him or her:

  • Genetic test results show that a relative has had a gene fault
  • A family member was diagnosed with cancer when he or she was below the age of 50
  • Several relatives had the same type of cancer
  • Several relatives had different cancers but was caused by the same gene fault
  • More than two paternal or maternal relatives have had cancer

Cancer is most common in individuals who have passed the age of 60. The disease is rarer in young individuals. The cause of cancer in older individuals is less likely due to inherited cancer genes.

No Fear – “Nature” Plays a Minor Role

Today, many individuals are still mistaken that heredity and genes play a major role in cancer risk and death. WHO has clarified that over 30 percent of cancer-related deaths can be prevented when one avoids the following key risk factors, e.g. high body mass index (BMI), tobacco use, alcohol use, lack of physical activity, and low vegetable and fruit intake. Cancer-causing viral infections, e.g. HPV and HBV/HCV, are responsible for up to 20 percent of cancer-related deaths. This is common in low-income and middle-income countries.

According to the National Cancer Institute (NCI), between five and 10 percent of all cancers are due to inherited genetic mutations.

In other words, genetics play a minor role in cancer risk. It is how one’s genes interact with the environment, and how that interaction affects one’s health.

Bad Lifestyle Choices Increase One’s Cancer Risk – “Nurture”

Remember, cancer can develop due to simple random errors in the way cells replace themselves in one’s body. These random cancers are only a part of the picture. Lifestyle factors are still an important part of the equation. One increases the risk of cancer if he or she:

  • Drinks alcohol on a daily basis: Long-term and chronic use of alcohol can lead to cancers pertaining to the breasts, rectum, colon, liver, throat, and mouth.
  • Has a high BMI: A healthy BMI for men and women is usually between 18.5 and 24.9. 25 means the individual is overweight. 30 means that the individual is obese. Obese individuals are at a higher risk of developing bowel, pancreas, esophagus, gallbladder, liver, prostate, ovary, breast, kidney, or womb cancers.
  • Has poor dietary habits: One can increase cancer risk if he or she eats too much salt, consumes high-calorie drinks and foods, eats too little fruits/vegetables/grains, and does not cut down on processed and red meat intake. Excessive consumption of preserved meats can cause bowel cancer.

Fortunately, the American Cancer Society has mentioned that it’s possible to prevent over 50 percent of all cancer deaths. Making healthy lifestyle changes is one way.

Nature Vs. Nurture | High Risk Genes Vs. High Risk Lifestyle

All factors play a part. As mentioned, cancer can be caused by gene mutation—chance—and/or poor lifestyle choices. It’s how you choose to bridge the gap between nurture and nature. Although some cancers can’t be completely prevented via lifestyle modifications alone, one can reduce his or her risk of developing certain diseases by adopting healthier practices.

If you have a strong family history of cancer, consult your general practitioner. You may be referred to a genetics clinic if you are found to be at increased risk.

If you suspect that you have a gene fault and want to know how your cancer risk compares toward the general population, speaking to a genetic counsellor or a doctor is a good idea. In this case, you might need to undergo regular monitoring for certain cancers.