title: Extra copies of c-myc are more pronounced in nodular melanomas than in superficial spreading melanomas as revealed by fluorescence in situ hybridisation.
abstract: BACKGROUND
  Amplification of c-myc is a common genetic alteration and associated with a poor prognosis in a variety of cancers. Extra copies of the gene have been found in large numbers of melanoma metastases, but only few primary tumours have been studied. We investigated the c-myc copy number alterations in two different subtypes of primary melanomas with different biological behaviours.
  
  
  METHODS
  Fluorescence in situ hybridisation was performed using c-myc and centromeric 8 (C8) probes on 68 lesions (28 nodular melanomas [NMs], 26 superficial spreading melanomas [SSMs], and 14 metastases). To assess the ploidy pattern, copy number distribution of seven different chromosomes was also investigated.
  
  
  RESULTS
  All tumours showed aneuploid populations for at least three chromosomes. Whereas 61% of the NMs exhibited extra c-myc copies, only 27% of SSMs showed increased gene dosage. The c-myc/C8 ratio exceeding 1.5 was significantly higher in NMs (P = 0.01). High level amplification was seen only in NMs. An elevated c-myc/C8 ratio was higher than 1.5 in only four metastases.
  
  
  CONCLUSIONS
  Our data show that c-myc copy number alterations differ in the two melanoma subtypes and are associated with the advanced stage of the disease. The less frequent amplification of the c-myc gene in metastatic lesions indicates that it may play an important role in the development of an invasive potential rather than in the metastatic process.
authors.affiliation: Department of Preventive Medicine, School of Public Health, Medical and Health Science Centre, University of Debrecen, Debrecen, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Treszl
authors.forename: Róza
authors.initials: R
authors.lastname: Adány
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Rákosy
authors.forename: László
authors.initials: L
authors.lastname: Kardos
authors.forename: Agnes
authors.initials: A
authors.lastname: Bégány
authors.forename: Katalin
authors.initials: K
authors.lastname: Gilde
authors.forename: Margit
authors.initials: M
authors.lastname: Balázs
mesh_terms: D000328:Adult; D000367:Age Factors; D002503:Centromere / Q000235:genetics; D005260:Female; D018628:Gene Dosage; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008545:Melanoma / Q000235:genetics* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D011003:Ploidies; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D016271:Proto-Oncogene Proteins c-myc