title: [Expression of hMLH1 in rectal intraepithelial neoplasm and early rectal carcinoma].
abstract: OBJECTIVE
  To explore whether the abnormality of hMLH1 gene may be an early event of carcinogenesis in rectal carcinoma, and to evaluate the diagnostic value in differentiation between intraepithelial neoplasm and early stage of colorectal carcinoma.
  
  
  METHODS
  The expression of hMLH1 protein in 28 cases with early invasive rectal carcinoma(EIRC), 36 cases with rectal intraepithelial neoplasm(RIEN), and 30 cases with normal rectal mucosa(NRM) which were collected through surgical operations were detected by PV-9000 immunohistochemical method.
  
  
  RESULTS
  The positive expression rates of hMLH1 protein were 100%(30/30), 77.8%(28/36), and 39.3%(11/28) in NRM, RIEN, and EIRC respectively. The difference was statistically significant between RIEN and EIRC(P=0.002), and the difference was also statistically significant between RIEN and NRM(P=0.006). The positive expression of hMLH1 was not related to age, gender, tumor maximum diameter, dysplasia, tumor types, and distance from the anal verge in RIEV group(P>0.05). In EIRC group, hMLH1 was associated with tumor differentiation(P<0.05).
  
  
  CONCLUSIONS
  hMLH1 gene deletion may be an early event during carcinogenesis of rectal carcinoma, which may be useful in differentiation of intraepithelial neoplasm from early rectal carcinoma.
authors.affiliation: Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Zhi-xuan
authors.initials: ZX
authors.lastname: Xuan
authors.forename: Guo-le
authors.initials: GL
authors.lastname: Lin
authors.forename: Xin-ming
authors.initials: XM
authors.lastname: Yu
authors.forename: Hui-zhong
authors.initials: HZ
authors.lastname: Qiu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000378:metabolism*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1