Among them, circulating DNA released by tumor cells can detect tumor gene mutation as low as 1% by the latest high-throughput sequencing technology, and the clinical accuracy is still high. Therefore, the quantitative analysis of DNA in tumor cells mainly focuses on the degree of cell atypia, distinguishing between cancer and precancerous lesions.
Every normal cell has a fixed DNA content, usually in the unit of DNA index or C (content). When the cell is in G 1/G0 phase, the DNA content of the cell is DI= 1 or 2c. When the cell is in the proliferative phase, the DNA content can be doubled and expressed as DI=2 or 4c.
In the process of cell carcinogenesis, the size of the nucleus, the content of DNA in the nucleus and the distribution and arrangement of DNA in the nucleus will all change, and this change is the earliest change in the process of cell carcinogenesis.
& gt5c refers to 82 cells with more DNA than normal.
Extended data:
On June 5438+09, Science magazine published online the research of Cao Xuetao, an academician of China Academy of Engineering and president of Nankai University. It is found that there are natural immune receptor molecules in the nucleus, which can specifically recognize the virus DNA and launch a "strong counterattack" against the virus.
The key of the whole new mechanism is the protein molecule of heterogeneous ribonucleoprotein A2B 1. "hnRNP-A2B 1 is described as a' militia', but a' civilian' at ordinary times, and is responsible for transporting mRNA. When it encounters a virus attack, it becomes a' soldier' and moves from the nucleus to the cytoplasm through changes such as protein's' fusion' and methylation, activating natural immune signaling pathways and starting antiviral effects. "
This discovery reveals a new mechanism of nuclear protein molecules participating in natural immune recognition and signal transduction, and provides new ideas and potential new targets for antiviral therapy and prevention and treatment of inflammatory diseases.
People's Daily Online-China team found virus DNA recognition molecules in the nucleus.