What is the current status and challenges of "genomic medicine"? Discussed at the symposium

A symposium on "genomic medicine," in which genes are examined and treated according to each patient, was held at the General Meeting of the Japan Medical Society, and we reported on the progress of diagnosis and treatment, such as the fact that doctors are becoming aware of the names of intractable diseases that are difficult to diagnose and lead to treatment.

Genomic medicine has become popular, especially in the field of cancer treatment due to the low cost of gene analysis, and at the symposium, doctors who are conducting research and treatment of genomic medicine for cancer and intractable diseases held discussions.

Among them, Professor Kenjiro Kosaki of Keio University School of Medicine created a network of nearly 400 medical institutions nationwide and analyzed the genes of patients with rare diseases that are difficult to diagnose, and found that nearly half of the approximately 7000,<> families had hereditary diseases, and in some cases they led to treatment.

On the other hand, since genomic medicine shows the susceptibility to diseases through tests, there are concerns and ethical issues of unfair discrimination in terms of insurance, employment, marriage, etc., and the Japan Medical Society and other organizations issued a statement last year calling for the immediate development of legislation to prevent discrimination.

Dr. Hiroyuki Mano, Director of the National Cancer Center Research Institute, who chaired the symposium, said, "Genomic information is the ultimate personal information, and it is necessary to establish a system that does not suffer disadvantages and a mechanism to use it in a better direction.

Cancer treatment can be improved by genomic medicine

A new cancer treatment method that examines the genes of cancer patients to select the optimal therapeutic agent is called "cancer genomic medicine," and it was applied by public insurance in June 2019 and is becoming widespread.

In cancer genomic medicine, the most suitable therapeutic drug is selected for the patient after undergoing a "gene panel test" to check for mutations in up to 6 or more genes that have been pointed out to be related to the development of cancer, and according to the National Cancer Center, about 300,2 people have undergone this test by February. In some cases, cancer symptoms improved as a result of receiving anticancer drugs suitable for the individual after being tested.

Last year, a woman in her 5s who visited the National Cancer Center underwent gene panel testing when rare skin cancer had progressed to the liver and there was no effective treatment. When he was given a "molecular-targeted drug" that responded to the genetic mutation found in the test, the cancer that was more than 70 centimeters became 7 centimeters in about half a year, and symptoms such as malaise subsided, and he continued treatment while working.

Noboru Yamamoto, Deputy Director of the National Cancer Center Hospital, who was in charge of the treatment, said, "We were surprised because we didn't expect such an effect in about six months."

On the other hand, among those who have undergone gene panel testing, only about 2% of patients who can actually receive treatment after finding a therapeutic drug corresponding to the gene mutation are found, and Deputy Director Yamamoto said, "Even if a genetic mutation is found, there are many cases where there is no therapeutic drug that can be used. I think the number of patients who can receive treatment suitable for each of them will increase."

There are also studies that estimate the risk of various diseases

Research is also underway to estimate the risk of not only cancer but also lifestyle-related diseases and various other diseases through genome analysis.

Professor Sukezo Okada of the University of Tokyo Graduate School is conducting research to find mutations in genes associated with the risk of developing diseases by analyzing the genetic information of tens of thousands of people with more than 300 types of diseases and constitutions, including patients with diabetes, myocardial infarction, rheumatoid arthritis, and people with high levels of cholesterol.

Some gene mutations that lead to the risk of developing diseases are very strongly associated with the onset of diseases, and some are not strongly related to the onset of disease, but the risk of disease increases when multiple mutations are accumulated, and Professor Okada estimates the high risk of developing a specific disease by examining and calculating how many mutations there are in genes.

This method is called the "polygenic risk score" and is being studied in various countries as it leads to the prevention and early detection of diseases.

Professor Okada said, "Analysis has shown that lifestyle-related diseases and other diseases that affect many people are caused by a combination of not only specific genes but also thousands of gene mutations, leading to the onset of diseases. I'm talking.

Regarding the "Polygenic Risk Score," a venture company established by doctors at Fujita Health University in Aichi Prefecture has been conducting tests to determine the genetic risk of disease by collecting saliva and analyzing genes for patients who have been visiting university hospitals since last year.

Based on the information in the database created by Professor Okada and others that analyzed the relationship between genes and diseases, this company examined 40 types of diseases such as diabetes, cancer, and high blood pressure, and 25 types of constitutional characteristics such as high cholesterol levels and uric acid levels in the blood. It analyzes how much risk there is and shows it together with knowledge of the disease and prevention methods.

Professor Masashi Ikeda of the Graduate School of Nagoya University, who serves as the president of this company, says, "A high genetic risk does not necessarily mean that you will get sick, but because of the high risk, we hope that it will be an opportunity to change lifestyle habits and other behaviors for prevention.

There are challenges in handling genetic information

Some doctors in charge of genetic testing for cancer have experienced cases where patients who underwent surgery for hereditary colorectal cancer received inquiries from insurance companies about test results when they claimed medical insurance payments, resulting in delays in payment of benefits.

Dr. Sana Yokoi, Director of the Department of Genetic Diagnosis at the Chiba Cancer Center, is in charge of the Cancer Genome Outpatient Clinic, which diagnoses hereditary diseases and selects the most suitable therapeutic drug according to differences in patients' genetic information.

According to Dr. Yokoi, when a man in his 20s who underwent endoscopic surgery for hereditary colorectal cancer last year filed a claim for benefits from a non-life insurance company, he received two written inquiries about the man's genetic disease.

After taking out insurance, the man underwent genetic testing because his parents had hereditary colon cancer, and when he underwent genetic testing, he was diagnosed with "Lynch syndrome," which increases the risk of developing colorectal cancer at a young age, and he actually developed hereditary colon cancer last year.

Mr. Yokoi said that at the end of May last year, the insurance company to which the man belonged said that he had to notify the insurance company of "lynch syndrome" at the time of enrollment, and that he received an inquiry through a research company about the background of the diagnosis and the details of the test results.

Mr. Yokoi accepted that he had received an inquiry about the results of genetic testing, and refused to respond to the insurance company on the grounds that it violated the statement issued by the General Insurance Association of Japan on May 5 last year that "we do not collect or use the results of genetic tests for insurance enrollment and payment."

After that, as a result of consultation with the insurance company, the benefits were paid more than half a year after the procedure began.

Director Yokoi said that this was a case in which patients could have suffered disadvantages, and that "the development of a legal system that stipulates the handling of genetic information should be promoted as soon as possible."

On the other hand, the General Insurance Association of Japan has confirmed the facts with the insurance company in question, but it has said that insurance companies that have been members of the association do not use genetic information.