Dr. Tsubokura's Radiation Lecture Vol.99

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

197. An elevated risk of cancer could run in the family

According to recent statistics, in Japan, around one in every two people will develop cancer in his or her lifetime. Furthermore, cancer deaths account for one in every five deaths in the country. Cancer is one of the common diseases in the country.

There are various causes of cancer, including eating habits, heavy drinking and smoking, infectious diseases, and radiation exposure. In addition to these causative factors that are closely related to our lives and to the environment, it is known that cancer can be inherited as well. Needless to say, hereditary cancer does not mean that cancer cells themselves are inherited. Rather, it means that children inherit an increased cancer risk from their parents.

For instance, there is a condition called familial colorectal cancer that poses an elevated risk of developing colorectal cancer among the affected families. In this population, gene mutations that cause errors in deoxyribonucleic acid replication have been identified, and they contribute to cancer development.

However, these genes are rarely identified in most of cases. This is because most cancers develop not because of a single reason but rather because of multiple causes. Thus, the prevention of cancers requires an understanding of various risk factors for cancers and controlling them in a well-balanced manner.

198. Cancer is similar to “a car being out of control”

According to recent statistics, in Japan, around one in every two people will develop cancer in his or her lifetime. Furthermore, it has been reported that cancer deaths account for one in every five deaths in the country. This means that cancer has become one of the common diseases in Japan. To foster an understanding of the current problems associated with cancer, in this article, I would like to explain the basic characteristics and mechanism of cancer.

When we are driving, we control the vehicle by pressing the accelerator and brake pedals using the appropriate timing. However, when the accelerator pedal is pressed firmly for a long time, or if the brake pedal is broken down, the car will not be able to stop, and eventually, this will lead to an accident.

Comparably, cells in our body also have a similar function to this accelerator and brake pedals. Depending on the state of the body, cells either proliferate (accelerator) and stop their growth (break) as appropriate. For example, when an injury occurs on the arm, skin cells proliferate and close the wound, but when the wound heals, they stop multiplying.

On the other hand, cancer cells continue to grow and proliferate because their accelerator and brake functions are broken. As cancer cells continue to grow with no control, they interrupt the vital functions of surrounding organs and metastasize and multiply in other locations.

When the accelerator and brake functions are broken, it is referred to as genetic damage, which can be caused by a variety of factors, including radiation exposure and unhealthy lifestyle habit.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, 21st and 28th October 2018 was reproduced for MRIC Global under the author's permission.