title: Pathologic assessment of melanoma sentinel nodes: a role for molecular analysis using quantitative real-time reverse transcription-PCR for MART-1 and tyrosinase messenger RNA.
abstract: OBJECTIVE
  Molecular analysis of melanoma sentinel nodes (SN) is sensitive, but poorly specific because metastases cannot be distinguished from benign nevus inclusions (BNI). We investigated whether quantitative reverse transcription-PCR (RT-PCR) detection of MART-1 and tyrosinase mRNAs could improve this specificity and contribute to SN assessment.
  
  
  METHODS
  Two hundred twenty SNs from 95 melanoma patients analyzed by extensive immunohistopathology and real-time quantitative RT-PCR.
  
  
  RESULTS
  Using histopathology, SNs and patients were allotted to three diagnostic groups: (a) metastasis positive, (b) BNI positive, and (c) melanocyte-free. Median MART-1 and tyrosinase mRNA levels in SNs were significantly different in patients with metastasis compared with patients with BNIs (P < 0.05) and patients without melanocytic lesions (P < 0.001). However, a "gray-zone" was observed where distinction, based on mRNA levels, could not be made between the three groups. For both genes, the highest mRNA level recorded in each RT-PCR-positive patient was positively correlated with Breslow's tumor thickness. For SNs with metastases, tumor burden was significantly correlated to the mRNA level. Using the presence of a MART-1 RT-PCR signal to detect patients with metastases, a sensitivity of 100% and a negative predictive value of 100% were achieved when extensive immunohistology was used as reference.
  
  
  CONCLUSIONS
  Quantitative RT-PCR MART-1 and tyrosinase mRNA analysis cannot be used alone for SN diagnosis because of its poor specificity for melanoma metastasis. However, in approximately one third of cases without RT-PCR evidence of MART-1 expression, extensive histopathologic SN investigation is not necessary, thus substantially reducing the cost of SN analysis. The level of melanocyte-associated mRNA is associated with both tumor thickness and tumor burden as measured histopathologically, suggesting that this may be of prognostic value.
authors.affiliation: Institute of Pathology, Aarhus University Hospital, Aarhus Sygehus, Noerrebrogade 44, DK-8000 Aarhus C, Denmark. abrahamsen@dadlnet.dk
authors.forename: Helene Nortvig
authors.initials: HN
authors.lastname: Abrahamsen
authors.forename: Boe Sandahl
authors.initials: BS
authors.lastname: Sorensen
authors.forename: Ebba
authors.initials: E
authors.lastname: Nexo
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hamilton-Dutoit
authors.forename: Jørn
authors.initials: J
authors.lastname: Larsen
authors.forename: Torben
authors.initials: T
authors.lastname: Steiniche
mesh_terms: D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000235:genetics; D058965:MART-1 Antigen; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000473:pathology*; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021701:Sentinel Lymph Node Biopsy
chemical_list: D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D014442:Monophenol Monooxygenase