The research group of Professor Issei Imoto, Associate Professor Kiyoshi Masuda, and Associate Professor Eigo Otsuji and Associate Professor Daisuke Ichikawa of the Department of Gastroenterological Surgery, Kyoto Prefectural University of Medicine, is in the blood. We have developed a method that can detect HER2 gene amplification, which is the target of molecular-targeted therapeutic agents in gastric cancer, with high sensitivity and high accuracy and with minimal invasiveness by using the technology to analyze DNA derived from cancer.By being able to diagnose with blood, it will be possible to monitor recurrence and predict / determine the therapeutic effect in real time, which may be a useful tool for future gastric cancer treatment.
Activation of the HER2 molecule by HER2 gene amplification may cause malignancy of breast and gastric cancer.Currently, positive and negative diagnoses are made using the cancer tissue at the time of surgery, and drug treatment with molecular-targeted therapies can be performed when the cancer recurs.However, even in HER2-positive gastric cancer, the effect of the molecular-targeted drug is low if the number of HER2-amplified cells is not increased in the recurrent cancer, and even in the case of HER2-negative, a small number of HER2 amplified cells in the cancer are overlooked. Therefore, if it increases at the time of recurrence, it cannot be treated with a molecular-targeted drug.Taking cancer tissue by re-examination is also considered to be highly invasive.
The newly developed method for determining the presence or absence of HER2 gene amplification from cancer-derived DNA flowing in the blood can be performed as many times as necessary with minimal invasiveness because it can be determined only by collecting blood.By using a digital technology called the Droplet digital PCR method, the group has become able to detect with more stability, high sensitivity, and high accuracy, and is approaching practical use in clinical practice.
This study provides some clinically important findings, and we also found that by confirming the value indicating the degree of HER2 amplification, it can be used as a marker for recurrence monitoring and therapeutic effect.In the future, the research group will increase the number of cases and confirm its clinical usefulness, and will proceed with further technological development for the practical application of the test.