Method and system for detecting microsatellite instability states

Abstract

The present invention relates to the technical field of detection of microsatellite sites, in particular to a method and system for detecting instability of microsatellites. DNA is extracted from cancerous tissue samples, fragmented, end repaired, and jointed; and then amplified , hybridization, capture, PCR amplification, and purification to obtain a sequencing library; obtain targeted capture sequencing data of tumor tissue samples through second-generation sequencing, and analyze information related to microsatellite instability detection based on the MSI model. Compared with the existing technology, the present invention adopts the current mature next-generation sequencing technology to obtain the genetic information of the tumor tissue of the test subject, can analyze a single tumor tissue, does not rely on control samples, breaks the limitation of microsatellite detection, and is applicable Based on the combination of multiple genes, there is no need to specially design MSI site probes, the applicability is strong, and the detection cost can be saved. It is efficient, systematic, economical and simple, and improves the sensitivity of detection.

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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