title: New primers for methylation-specific polymerase chain reaction enhance specificity of detecting STAT1 methylation.
abstract: OBJECTIVE
  Signal transducer and activator of transcription (STAT)1 is a key tumor suppressor, which is always methylated in a variety of human cancers. However, nonspecific primers for the detection of specific promoter hypermethylation of STAT1 gene can lead to false-positive or false-negative results for gene methylation.
  
  
  METHODS
  We designed new primers for the detection of STAT1 methylation and compared the sensitivities and specificities of these new primers with prior published primers by methylation-specific polymerase chain reaction (PCR) from ovarian clear cell carcinomas. The mRNA expression levels of STAT1 in these cancerous tissues were also evaluated by reverse-transcriptase PCR and correlated with the results of promoter methylation of STAT1 gene.
  
  
  RESULTS
  Nine (39%) of the 23 samples detected by the new primers and 13 samples (56%) detected by prior published primers showed STAT1 methylation. A direct DNA sequencing test revealed that four of the 13 samples (30.8%) showed false positivity for STAT1 methylation using the prior published primers. In contrast, none of the nine samples was false-positive for the detection of STAT1 methylation using the new primers. The new primers for the detection of STAT1 methylation showed 100% specificity and 100% sensitivity without false positivity.
  
  
  CONCLUSIONS
  Specific primers for methylation-specific PCR are mandatory for the accurate detection of STAT1 gene methylation. Besides, specific primers can generate correct interpretation of STAT1 gene methylation, and its correlation with the clinicopathological characteristics and outcome of cancer patients.
authors.affiliation: Department of Obstetrics and Gynecology, Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Ming-Cheng
authors.initials: MC
authors.lastname: Chang
authors.forename: Ying-Cheng
authors.initials: YC
authors.lastname: Chiang
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Ho
authors.forename: Yu-Li
authors.initials: YL
authors.lastname: Chen
authors.forename: Chi-An
authors.initials: CA
authors.lastname: Chen
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Cheng
authors.forename: Cheng-Yang
authors.initials: CY
authors.lastname: Chou
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000235:genetics*; D019175:DNA Methylation; D017931:DNA Primers; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000235:genetics*; D012680:Sensitivity and Specificity
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human