Stomach cancer is the third leading cause of cancer death worldwide. But for us in Asia, stomach cancer is a bit special, because the incidence of stomach cancer is particularly pronounced in East Asia. Is it genetic, or lifestyle habits such as diet, or some interaction between the two that makes East Asians susceptible to stomach cancer?
Recently, the University of Tokyo and other Japanese research institutions to complete a study, for us to better prevent stomach cancer provides important information. The researchers analyzed the genomic data and lifestyle of 531 patients with stomach cancer, comparing data from 300 Asians and more than 200 non-Asians to the three main factors that Asians are prone to stomach cancer: smoking, drinking, and a genetic mutation specific to East Asians. The findings were published in Science Advances, a sub-journal of Science.
The researchers first performed a full-out appearance-based sequence analysis of more than 500 gastric cancer patients. As we understand the occurrence of cancer, the cancer cell genome during cancer is characterized by a variety of specific somatic cell mutations. Depending on the mutation characteristics, the researchers divided the stomach cancer cases into six groups.
In one group, they noted some characteristics: cancer mutations have a relatively low burden, with one in five diffuse stomach cancers, but more crucially, more than 90 percent of cases are Asian, and 70 percent of patients have a well-known gene mutation, ALDH2.
THE MUTATION OF ALDH2 IS COMMON AMONG EAST ASIANS. This gene-coded protein plays a key role in alcohol metabolism, while the unique mutation type in East Asians can greatly reduce the activity of the protein, so alcohol intake can not be metabolized in a timely manner, resulting in a common manifestation is that after drinking alcohol prone to skin redness.
Drinking is prone to blush because a genetic defect causes a key enzyme responsible for alcohol metabolism in the body to be underactive (Photo: Pixabay)
Next, the researchers conducted an in-depth analysis of the Japanese case of this subtype of stomach cancer, especially the relationship between lifestyle habits and the genome. They concluded that drinking alcohol and the ALDH2 mutation gene were important reasons for the high incidence of this type of stomach cancer in the Asian population. In particular, most of these stomach cancer patients do not drink heavily. In other words, because of the specific genetic defects, even a small amount of alcohol can put them at greater risk of stomach cancer.
The researchers also continued to examine the effects of smoking, given that drinking and smoking often “work together” to increase the risk of the disease in another type of cancer common in East Asians, esophageal cancer. After analyzing the detailed causes of stomach cancer in Japan, the researchers found that smoking did not have synergies with alcohol in people with ALDH2, and for those who did not drink, smoking did not increase the risk further. However, if there is an ALDH2 defect and drinking, the consequences of alcohol and tobacco are worse, and the risk of developing stomach cancer increases further.
Japanese researchers have produced a very easy-to-understand summary (Photo: Resources 2; Credit: Akihiro Suzuki, Hiroyuki Aburatani, Hiroto Katoh, Shumpei Ishikawa)
In summary, this finding reveals the interaction between genetic tendency and living habits, which has important clinical and social significance on the risk of stomach cancer in East Asian population. Guided by these results, we may wish to target interventions such as early detection of people at high risk of stomach cancer through genetic susceptibility, smoking cessation, and improving lifestyle habits to minimize the risk of stomach cancer.