Researchers in the United States have developed a new way to detect cancer cells. With a new blood test, they can determine a patient's condition by identifying the pieces of DNA characteristic of cancer cells released into the blood after they have been cleaved. The technique is sensitive and accurate enough to detect individual "outliers" in hundreds of millions of healthy blood cells.
    The mortality rate of cancer is extremely high. It is particularly important to detect the early signs of cancer. However, the high cost of money and time actually makes ordinary people feel inconvenient. A simple blood test that can pick up signs of cancer proliferation is a quick fix for many people. Scientists believe that tumors need blood to grow, and that blood may contain information left behind by cancer cells. "It's a liquid-like biopsy that avoids pain and is a better way for doctors to monitor the development of cancer cells than a conventional imaging scan," said Dr. Robert Haber, director of the cancer center at Massachusetts general hospital, who was involved in the test.

    This idea has encountered many difficulties in practical operation. It is generally believed that in both cases, the proliferation of cancer cells is at a mild stage. Therefore, the amount of DNA samples is small compared with the amount of DNA in normal blood. Therefore, it is very difficult to find the mutated DNA. In addition to DNA mutations, scientists think they can be detected through epigenetics. Scientists believe that different tissues leave different methylation modifications on DNA, and analyzing the degree of DNA methylation modification can infer the source of DNA. They tested this idea and effectively detected circulating tumor DNA by analyzing methylation changes. To address the low overall level of cfDNA, they optimized the process using immunoprecipitation techniques, supplemented by high-throughput sequencing analysis.
    The researchers obtained plasma cfDNA from 24 patients with early-stage pancreatic cancer and compared it with samples from another 24 healthy people. By comparing the two groups of samples, the number of CpG with different modifications was 45,172.This data is enough to show that we can find DNA from tumors using this technique.
    Of course, this technology still needs more data verification, and it is hoped that in the near future, detection of cancer can be simple and easy, early detection and early treatment can be achieved.