title: [Incidence and Characteristics of Mismatch Repair Protein Deficiency in Elderly Gastric Cancer Patients].
abstract: The loss of mismatch repair(MMR)function as a result of MLH1 promoter methylation is closely correlated with high frequency microsatellite instability, and tumors with such characteristics are resistant to anticancer drugs such as 5-FU. We examined the incidence and characteristics of deficient MMR(dMMR)in elderly gastric cancer patients by performing a comprehensive immunohistochemical screening. The study was conducted in 199 patients diagnosed with gastric cancer, aged 75 years or older, who underwent a gastrectomy between April 2005 and January 2014. dMMR was detected in 23 patients(12%). All the tumors with dMMR were deficient in MLH1 and PMS2. dMMR was significantly more common compared to proficient MMR(pMMR)in patients with a more advanced age(p=0.03), women(p<0.01), and a tumor location corresponding to the lower region(p<0.01). Considering the incidence of dMMR in elderly gastric cancer patients, only a limited proportion of patients are likely to be eligible for immune checkpoint inhibitor therapy, which is expected to become more popular in the near future.
authors.affiliation: Dept. of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University.
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Chika
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuchi
authors.forename: Okihide
authors.initials: O
authors.lastname: Suzuki
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ito
authors.forename: Azusa
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Toru
authors.initials: T
authors.lastname: Ishiguro
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kumagai
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Erito
authors.initials: E
authors.lastname: Mochiki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ishida
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053843:DNA Mismatch Repair; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000235:genetics*