title: An optimal mRNA marker for OSNA (One-step nucleic acid amplification) based lymph node metastasis detection in colorectal cancer patients.
abstract: BACKGROUND
  We previously reported that the one-step nucleic acid amplification assay is effective for lymph node metastasis detection in breast cancer patients. This paper describes the identification of CK19 mRNA as an optimal marker and its cut-off value for use in the detection of one-step nucleic acid amplification-based lymph node metastasis in colorectal cancer patients.
  
  
  METHODS
  Candidate mRNA markers selected from the genome-wide expressed sequence tag database were evaluated by quantitative RT-PCR using a mixture of metastasis-positive and another mixture of metastasis-negative lymph nodes (n = 5 each), followed by quantitative RT-PCR using metastasis-positive and -negative lymph nodes (n = 10 each) from 20 patients. The one-step nucleic acid amplification assay for mRNA markers selected above was examined using 28 positive lymph nodes from 19 patients and 38 negative lymph nodes from the 11 pN0 patients.
  
  
  RESULTS
  Quantitative RT-PCR analyses of the 98 mRNAs selected from the genome-wide expressed sequence tag database and the subsequent quantitative RT-PCR analyses of the nine mRNAs selected above indicated that CK19 and CEA mRNAs have the highest capability for distinguishing between positive and negative lymph nodes. CK19, CEA and CK20 mRNAs were evaluated by the one-step nucleic acid amplification assay. An area under a receiver-operating-characteristic curve for CK19 mRNA (0.999) was slightly larger than that for CEA mRNA (0.946; P = 0.062) and significantly larger that than for CK20 mRNA (0.875; P = 0.006).
  
  
  CONCLUSIONS
  We found that CK19 mRNA has the best diagnostic performance and its cut-off value for discriminating positive from negative lymph nodes can be set in the range of 75-500 copies/µl with 96.4% sensitivity and 100% specificity.
authors.affiliation: Central Research Laboratories, Sysmex Corporation, 4-4-4 Takatsukadai, Kobe, Hyougo, Japan. otomo.yasuhiro@sysmex.co.jp
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Motonari
authors.initials: M
authors.lastname: Daito
authors.forename: Kayo
authors.initials: K
authors.lastname: Hiyama
authors.forename: Junyi
authors.initials: J
authors.lastname: Ding
authors.forename: Kadzuki
authors.initials: K
authors.lastname: Nakabayashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Otomo
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tsujimoto
authors.forename: Nariaki
authors.initials: N
authors.lastname: Matsuura
authors.forename: Yo
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D005260:Female; D006801:Humans; D053539:Keratin-19 / Q000235:genetics; D053554:Keratin-20 / Q000235:genetics*; D008207:Lymphatic Metastasis / Q000235:genetics*; D008297:Male; D021141:Nucleic Acid Amplification Techniques; D012333:RNA, Messenger / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D053539:Keratin-19; D053554:Keratin-20; D012333:RNA, Messenger