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    Home > Active Ingredient News > Digestive System Information > Eur J Hum Genet: Professor Ding Peirong explains that the initial screening results for Lynch syndrome are MSI-H/dMMR, what next step should be to test?

    Eur J Hum Genet: Professor Ding Peirong explains that the initial screening results for Lynch syndrome are MSI-H/dMMR, what next step should be to test?

    • Last Update: 2020-07-29
    • Source: Internet
    • Author: User
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    the !---- dMLH1 gene methylation test is an important screening method for Lynch syndromeIt is generally believed that MLH1 methylated colorectal cancer is the origin of distribution, can be exempted from germ line testing, saving socio-economic resourcesHowever, a recent study by Professor Ding Peirong of Sun Yat-sen University Cancer Hospital found that the test did not apply to screening Chinese group Lynch syndrome, direct embryo testing or optimal protocolThe study was published in the european journal European Journal of Genetics, The European Journal of Human GeneticsDing Peirong, Deputy Director, Professor, Chief Physician, Doctoral Mentor, FACS, Guangdong Province Outstanding Young Medical Talent (first batch), American Academy of Foreign Sciences (FACS), Visiting Scholar of Memorial Sloan Kettering Cancer Center (MSKCC), Deputy Chairman of the Family Genetic Oncology Professional Committee of the Chinese Cancer Society, Vice Chairman of the Youth Committee of the Chinese Society of Clinical Oncology (CSCO) Vice Chairman of the Gastroenterology Branch, Deputy Chairman of the Chinese Physicians Association's Special Committee on Colorectal Genetics, Vice Chairman of the MDT Professional Committee of the Chinese Physicians' Association Of Physicians Branch, Deputy Chairman of the Youth Committee of the MDT Professional Committee of the Chinese Physicians' Association, Consensus of Chinese Experts on Clinical Diagnosis and Treatment of Genetic ColorEctal Cancer and Family Management, Consensus of Experts on The Diagnosis and Treatment of TranslySexual Les Mod Side lymph nodes (2019), And Waiting for Observation Strategy ExpertS, Expert SedctAry Strategies After New Rectal Cancer Assistive TreatmentThe study context Lynch syndrome is the most common hereditary bowel cancer syndrome, accounting for about 3% of all colorectal cancersNot only do people with Lynch syndrome pass on the mutant gene to the next generation, but they also have a much higher risk of re-onsgeneration of their own tumors than in patients with common bowel cancerTherefore, it is of great clinical significance to identify this part of the patient in bowel cancer patientsA commonly used screening method is a "two-step" approach, in which MLH1 (-) patients are methylated to exclude dispersive patients as a result of MMR immunohesisBecause OF the "mutualexclusion" of MLH1 methylation and embryo MMR mutations, this screening strategy not only eliminates the exudative bowel cancer, but also has very few cases of "mistaken kick" Lynch syndrome, which is now widely used in Western countriesHowever, in Chinese group, the effectiveness of this screening strategy has not yet been confirmedOur previous study found that the incidence of BRAF mutation in patients with Chinese group of MLH1/PMS2 deficiency was significantly lower than in Western populations, suggesting that methylation testing was less effective in high-risk populationsTo this end, Professor Ding Peirong's team designed a research program to compare the efficacy and economic benefits of methylation testing and other screening strategies, and to explore screening strategies that are most appropriate for Chinese group Lynch syndromeThe method and results The researchers reviewed 3250 cases of colorectal cancer diagnosed at Sun Yat-sen University Cancer Prevention and Control Center from November 1, 2011 to December 31, 2015 with MMR protein test results, screened 170 patients with MLH1 (-) bowel cancer, and finally included 109 patients who had tested the embryo system and had tumor tissue samples, and were tested for MLH1 methylation and BRAF mutationThe researchers first assessed the effectiveness of mlH1 methylation strategiesIn 109 cases of MLH1 (-) colorectal cancer, there were 40 (36.7%) cases of MLH1 methylation, of which 39 (97.5%) were exudationThe sensitivity and specificity of this screening strategy were 95.7% and 45.3%, respectively In the economic benefit analysis, compared with direct sequencing, MLH1 methylation detection can reduce the cost of screening by reducing the number of sequencing, reducing the cost of detecting a case of Lynch syndrome from 15260 yuan to 13607 yuan On data alone, methylation testing appears to reduce screening costs, but it is important to note that the institute's sequencing costs include a 14-gene panel When the panel is reduced to five or even two genes (MLH1 and PMS2), or as sequencing technology matures and sequencing costs fall, the cost of screening and direct sequencing of methylation detection will be par Moreover, there is a risk of missed diagnosis Of the 23 cases of Lynch syndrome in the population tested, 1 (4.3%) were omitted Because MLH1 methylation is often associated with BRAF mutations, the researchers then evaluated the screening efficiency of BRAF testing They found that the braF mutation rate was only 5.5 percent in patients with MLH1 (-) colorectal cancer in China, far lower than in patients in Western countries Although this test is highly sensitive (100%), its specificity is only 7%, and the number of exuded bowel cancers that can be eliminated is too small to be screened Therefore, in the economic benefit analysis, this method of testing increases the cost of screening In addition, the researchers analyzed screening strategies combining MLH1 methylation testing with BRAF mutation testing and Besthesda standards, but none of them significantly reduced screening costs Conclusion The incidence of MLH1 methylation and BRAF mutation in colorectal cancer patients in China is lower than in western patients When screening Lynch syndrome in patients with colorectal cancer in MLH1(-), these two tests do not effectively reduce screening costs, direct embryo sequencing, or the best choice
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