Method and system for detecting microsatellite instability state

Abstract

The invention relates to the technical field of microsatellite site detection, in particular to a method and system for detecting the instability state of a microsatellite; and the method comprises the following steps: carrying out DNA extraction, fragmentation treatment, terminal repair and joint connection on a cancerous tissue sample; carrying out amplification, hybridization, capture, PCR amplification and purification to obtain a sequencing library; and obtaining targeted capture sequencing data of a tumor tissue sample through second-generation computer sequencing, and carrying out information analysis related to microsatellite instability state detection according to an MSI model. Compared with the prior art, the genetic information of the tumor tissue of the testee is obtained by adopting the current mature next-generation sequencing technology, single tumor tissue analysis can be carried out, dependence on a control sample is avoided, the limitation of microsatellite detectionis broken through, the method can be suitable for multiple gene combinations, an MSI site probe does not need to be specially designed, and the applicability is high; moreover, the detection cost canbe saved, the method is efficient, systematic, economic, simple and convenient, and the detection sensitivity is improved.

Description

technical field [0001] The invention relates to the technical field of microsatellite site detection, in particular to a method and system for detecting microsatellite instability states. Background technique [0002] Microsatellite (MS) sequences, also known as Short tandem repeats (STRs) or Simple Sequence Repeats (SSR), widely exist in prokaryotic and eukaryotic genomes and consist of 10 to 50 A highly polymorphic simple tandem repeat sequence formed by repeating units consisting of 1 to 6 nucleotides in series. When the human body's Mismatch repair (MMR) mechanism is defective, the length of the MS sequence will change, which becomes Microsatellite instability (MSI). A large number of studies have proved that microsatellite instability is related to the occurrence of tumors, especially gastrointestinal cancers such as colorectal cancer, and plays an important role in the treatment and prognosis of tumors. [0003] The National Comprehensive Cancer Network (NCCN) colore...

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Problems solved by technology

[0005] At present, most of the diagnostic methods for tumor MSI on the market stay at the detection level of single or several sites of a single tumor. These methods have different defects. The requirements are high, and the operation is also relatively complicated; the method of PCR usually selects 5-11 single nucleotide repeat sites, and the length is about 25bp. ) stable state, which is the current gold standard detection method, but requires additional detection samples, and requires the patient's normal tissue as a control to determine the state, so it is not convenient from an operational point of view

Therefore, the current MSI detection method is difficult to meet the current detection requirements such as a large number of detection samples, many detection sites, wide distribution, and high detection accuracy.

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