In recent years, circulating tumor DNA (circulating tumor DNA, ctDNA) in plasma has become a promising cancer biomarker, known as a “liquid biopsy.” CTDNA has proven to be useful in non-invasive detection of cancer, personalized treatment of advanced cancer, and monitoring during and after treatment.
However, the current testing research focuses on the detection of patients who have been diagnosed with cancer, what is the potential for early detection? On the evening of July 21st, Beijing time, the international academic journal Nature Communications published a study in which researchers from Fudan University, UCSD, Shandong University Qilu Hospital, Karolinska Medical School in Sweden, and Yuyuan Gene (Shanghai) reported that a non-invasive blood test could be used as a potential tool to detect five common cancers four years before a routine diagnosis.
The study, entitled “Non-early e e venture of cancer four years used sie s ss diagnosis a blood test”, was written by Ye Weimin, ADP Distinguished Researcher at the Taizhou Institute of Health Sciences at Fudan University and a tenured professor at the Karolinska School of Medicine in Sweden, and Associate Professor Gao Yuan, co-founder and chairman of the Yuyuan Gene. Professor of Bioengineering at the University of California, San Diego, Co-founder of Yuyuan Gene, Postdoctoral and Associate Researcher, Department of Bioengineering at the University of California, San Diego, Co-Founder and CTO Liu Wei, Executive Vice President of Fudan University, and Professor of the School of Life Sciences.
The five common types mentioned in the paper are stomach cancer, esophageal cancer, colorectal cancer, lung cancer and liver cancer. There are 261,530 deaths from these five cancers in the United States each year, and 2.1 million people die each year from these five cancers in China.
The team notes that if cancer is detected at an early stage, the survival rate of cancer patients can be greatly improved because it can be surgically removed or treated with the right medication. Data show that the average five-year survival rate for early cancer is 91%, while the average five-year survival rate for late stages drops to 26%. However, there are currently only a limited number of screening tests for several types of cancer, including colonoscopy, prostate-specific antigens, X-ray mammography, and cervical cytology.
Zhang said that although ctDNA has the potential for early diagnosis, there are still some obstacles. For example, the amount of tumor DNA in the plasma is limited, especially in the early stages, which may affect sensitivity. In addition, typical ctDNA mutation screening methods are prone to errors, resulting in reduced specificity, and the nature of cancer mutations also means screening for a large number of possible mutations for consistent biomarkers.
The team notes that an effective screening test must prove that asymptomatic cancer can be detected years before a routine diagnosis in a longitudinal study. In their paper, they showed that in a longitudinal study (TZL) conducted in Taizhou, Jiangsu Province, 123,115 healthy subjects provided plasma samples for long-term preservation, followed by monitoring cancer. The subjects were aged 25-90 and plasma samples were collected from 2007-2014.
By the end of 2017, 575 pre-diagnosis patients (initially asymptomatic) were diagnosed with one of the five common cancers within four years. The team further analyzed 191 of the 575 patients in the study, which also included plasma samples from 223 cancer-diagnosed patients, as well as 414 health samples.
Studies have shown that for patients diagnosed with five common types of cancer ,Post-diagnosis, PanSeer tests have an overall sensitivity of 88% (95% confidence interval: 80-93%), a specific 96% (95% confidence interval: 93-98%) for patients diagnosed with five common types of cancer, and 95% (95% confidence interval: 89-98%) for asymptomatic subjects.
The team believes the results suggest that a non-inlet test could detect five common cancers early four years before a routine diagnosis.
In addition, although PanSeer tests showed high sensitivity to cancer detection in plasma samples, the team observed that some genomic sites did not show consistent methylation changes between cancer tissue and cancer plasma samples. While this may be due to internal differences in tissue and plasma methylation, these inconsistencies may indicate unknown confounding factors.
As a result, the team further analyzed panSeer data. They identified 277 genomic regions that showed consistent methylation in tissue and plasma, and sensitivity and specificity remained high when modeling only those 277 genomic regions. This suggests that PanSeer can detect early-stage cancereven even under stricter settings.
The team stressed that PanSeer testing is unlikely to be predictive, but rather that it is most likely to identify patients who have cancer, but are asymptomatic under current conventional testing.
In the future, they said, in order to fully establish PanSeer’s clinical application sandinalation and fully validate pre-diagnosis test results for cancer, they hope to conduct a large-scale, healthy individual-looking study to determine whether non-invasive cancer screening can reduce cancer mortality in a cost-effective way.
It is worth mentioning that Zhang Wei, Gao Yuan and others in the United States in July 2014 set up the Yuyuan Group, in January 2015 registered the establishment of Shanghai Yuyuan, is committed to the development and promotion of high-throughput sequencing-based tumor diagnostic technology and products, the official website shows that the current completion of A-round financing and A-round financing.