title: Clinicopathological and molecular characteristics of serrated lesions in Japanese elderly patients.
abstract: BACKGROUND
  The population in Japan is aging more rapidly than in any other country. However, no studies have determined the characteristics of the large population of elderly patients with colorectal tumors. Therefore, we examined the clinicopathological and molecular features of these tumors in elderly patients.
  
  
  METHODS
  In total, 1,627 colorectal tumors (393 serrated lesions, 277 non-serrated adenomas and 957 colorectal cancers) were acquired from patients. Tumor specimens were analyzed for BRAF and KRAS mutations, CpG island methylator phenotype-specific promoters (CACNA1G, CDKN2A, IGF2 and RUNX3), IGFBP7, MGMT, MLH1 and RASSF2 methylation, microsatellite instability (MSI) and microRNA- 31 (miR-31).
  
  
  RESULTS
  The frequency of elderly patients (aged ≥75 years) with sessile serrated adenomas (SSAs) with cytological dysplasia was higher than that of those with other serrated lesions and non-serrated adenomas (p < 0.0001). In elderly patients, all SSAs were located in the proximal colon (particularly the cecum to ascending colon). High miR-31 expression, MLH1 methylation and MSI-high status were more frequently detected in SSAs from elderly patients than in those from non-elderly patients. In contrast, no significant differences were found between older age of onset and high-grade dysplasia for traditional serrated adenomas or non-serrated adenomas in any of these molecular alterations.
  
  
  CONCLUSIONS
  In elderly patients, all SSAs were located in the proximal colon. Furthermore, cytological dysplasia and molecular alterations were more frequently detected in elderly patients with SSAs than in non-elderly patients. Thus, careful colonoscopic examinations of the proximal colon are necessary for elderly patients because SSAs in those patients may exhibit malignant potential.
authors: Department of Gastroenterology, Rheumatology and Clinical Immunology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Katsuhiko
authors: K
authors: Nosho
authors: Hisayoshi
authors: H
authors: Igarashi
authors: Miki
authors: M
authors: Ito
authors: Kei
authors: K
authors: Mitsuhashi
authors: Hiroyoshi
authors: H
authors: Kurihara
authors: Shinichi
authors: S
authors: Kanno
authors: Shinji
authors: S
authors: Yoshii
authors: Masashi
authors: M
authors: Mikami
authors: Hiroaki
authors: H
authors: Takahashi
authors: Takaya
authors: T
authors: Kusumi
authors: Masao
authors: M
authors: Hosokawa
authors: Yasutaka
authors: Y
authors: Sukawa
authors: Yasushi
authors: Y
authors: Adachi
authors: Tadashi
authors: T
authors: Hasegawa
authors: Kenji
authors: K
authors: Okita
authors: Koichi
authors: K
authors: Hirata
authors: Reo
authors: R
authors: Maruyama
authors: Hiromu
authors: H
authors: Suzuki
authors: Kohzoh
authors: K
authors: Imai
authors: Hiroyuki
authors: H
authors: Yamamoto
authors: Yasuhisa
authors: Y
authors: Shinomura
mesh_terms: D000236:Adenoma / Q000235:genetics / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D003106:Colon / Q000473:pathology*; D003111:Colonic Polyps / Q000145:classification / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006965:Hyperplasia; D007564:Japan; D008297:Male; D053842:Microsatellite Instability; D009154:Mutation; D010641:Phenotype