title: Modal variety of microsatellite instability in human endometrial carcinomas.
abstract: OBJECTIVE
  Microsatellite instability (MSI) in human endometrial cancer (EC) was analysed using a unique fluorescent technique. MSI is associated with various human neoplasms. However, the reported frequency of MSI differs widely in each malignancy. Methodological difficulties have in fact been pointed out in its assay techniques.
  
  
  METHODS
  We previously established a sensitive fluorescent technique in which the major methodological problems are overcome. Application of this technique has revealed two distinct modes of microsatellite alterations, i.e. Type A and Type B. In the present study, we have applied this technique to 94 ECs.
  
  
  RESULTS
  Significant microsatellite alterations were observed in 38 (40.4%) tumours of the panel. The two modes, Type A and Type B, were indeed observed in this malignancy. More importantly, we found that the modes more closely correlated with the molecular and clinicopathological backgrounds of the tumours than the established and widely used MSI grades, MSI-H and MSI-L. Type B MSI widely correlated with family history of hereditary non-polyposis colorectal cancer-associated cancers, whereas MSI-H only did with that of colorectal cancer. Furthermore, mutation in the KRAS oncogene, which has been regarded as generally infrequent in microsatellite-unstable tumours, was clearly associated with Type A MSI.
  
  
  CONCLUSIONS
  Our observations may suggest a biological relevance and a potential utility of the modal classification of MSI and, furthermore, added complexities to genomic instability underlying tumourigenesis in human endometrium.
authors: Gynecology Service, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Takako
authors: T
authors: Eto
authors: The Third Surgery Department, Liaoning Cancer Hospital and Institute, Shenyang, 110042, The People's Republic of China.
authors: Yan
authors: Y
authors: Zhao
authors: Gynecology Service, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Akiko
authors: A
authors: Maruyama
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors: Kaname
authors: K
authors: Miyashita
authors: Clinical Research Institute, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Aiko
authors: A
authors: Yasui
authors: Clinical Research Institute, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Seiki
authors: S
authors: Nakao
authors: Clinical Research Institute, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Kenichi
authors: K
authors: Taguchi
authors: Clinical Research Institute, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Mototsugu
authors: M
authors: Shimokawa
authors: Clinical Research Institute, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan. soda@nk-cc.go.jp.
authors: Shinya
authors: S
authors: Oda
authors: Gynecology Service, National Kyushu Cancer Center, Fukuoka, 811-1395, Japan.
authors: Toshiaki
authors: T
authors: Saito
mesh_terms: D018269:Carcinoma, Endometrioid / Q000235:genetics*; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D016889:Endometrial Neoplasms / Q000235:genetics*; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D053842:Microsatellite Instability; D008875:Middle Aged; D017422:Sequence Analysis, DNA
chemical_list: D004273:DNA, Neoplasm; D005456:Fluorescent Dyes
keywords: DNA mismatch repair; Endometrial cancer; Familial predisposition; KRAS mutation; Microsatellite instability