title: Activation of the extracellular signal regulated kinase (ERK) pathway in human melanoma.
abstract: BACKGROUND
  Several studies suggest that melanoma may be resistant to treatment because of resistance to apoptosis and that this may be the result of activation of the extracellular signal regulated kinase (ERK1/2) pathway.
  
  
  OBJECTIVE
  To test this hypothesis by examining the expression of ERK1/2 and its activated form in histological sections of melanoma and its relation to known prognostic features of the disease.
  
  
  METHODS
  Immunohistochemistry with antibodies to ERK1/2 and phosphorylated ERK (p-ERK) was performed on formalin fixed sections from 42 primary melanomas, 38 metastases, and 20 naevi. Fourteen of the primary melanomas were in the radial and 28 in the vertical growth phase.
  
  
  RESULTS
  ERK1/2 was widely expressed (100%) in all the (pigmented) lesions studied. p-ERK1/2 expression was much lower in compound (32.4%) and dysplastic (54.5%) naevi than in primary melanoma (nodular 78.8%, superficial spreading 67%) and subcutaneous metastases (76.3%). p-ERK expression was much lower in lymph node metastases (48.5%), suggesting that the microenvironment may influence the activation of ERK. There was a (non-significant) trend for p-ERK expression to be higher in thick (>1.0 mm) versus thin (< or =1.0 mm) melanoma (p = 0.23). There was a trend for overall survival to be related to p-ERK expression in patients with melanoma over 1 mm in thickness.
  
  
  CONCLUSIONS
  Expression of activated ERK1/2 in melanocytic lesions appears to be related to malignant potential so that activation of ERK1/2 may be important in melanoma progression. These results provide important histological support for the proposal that inhibition of this signalling pathway may be useful in treatment of melanoma.
authors.affiliation: Department of Anatomic Pathology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Zhuang
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.forename: R A
authors.initials: RA
authors.lastname: Scolyer
authors.forename: S W
authors.initials: SW
authors.lastname: McCarthy
authors.forename: A A
authors.initials: AA
authors.lastname: Palmer
authors.forename: X D
authors.initials: XD
authors.lastname: Zhang
authors.forename: J F
authors.initials: JF
authors.lastname: Thompson
authors.forename: L P
authors.initials: LP
authors.lastname: Bron
authors.forename: P
authors.initials: P
authors.lastname: Hersey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D018450:Disease Progression; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009364:Neoplasm Recurrence, Local / Q000201:enzymology; D009508:Nevus, Pigmented / Q000201:enzymology; D010766:Phosphorylation; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000201:enzymology* / Q000473:pathology; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D048049:Extracellular Signal-Regulated MAP Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3