title: Nucleolar organizer region staining patterns in paraffin-embedded tissue cells from human skin cancers.
abstract: BACKGROUND
  Increased number of nucleoli (nucleolar organizer regions, NORs) with abnormal shapes and sizes, including small dots, has been used as prognostic tools to evaluate tumor proliferation levels and troublesome borderline lesions. In this study, NOR patterns of skin cancers were performed in the search of a valuable prognostic method to complement other histological procedures.
  
  
  METHODS
  Paraffin-embedded tumor tissue was obtained from basal and squamous cell carcinomas, cutaneous malignant melanoma, premalignant lesions, and Skmel-28 human melanoma cells. Slices were dewaxed and AgNOR stained. The patterns were scored and submitted for statistical analyses.
  
  
  RESULTS
  All types of cancer cells showed variable numbers of abnormally shaped nucleoli and dot-like structures. Only tumor cells presented four or more nucleoli, with or without dots, while 85% of the normal cells had one single NOR without dots. Most data were statistically significant when compared to normal cells. As a whole, squamous cell carcinoma and malignant melanoma tumor cells had less NOR alterations than basal cell carcinoma (BCC) tumor types.
  
  
  CONCLUSIONS
  Changes in the number and shape of nucleoli present in malignant cells could be attributed to increased levels on rDNA transcription on cancer cells, besides abnormal remodeling of chromatin, which could disrupt proper nucleoli association. Increased genetic alterations on malignant basal cells could contribute to impair invasive and migration abilities of BCC tumors.
authors.affiliation: Genetics Laboratory, Butantan Institute, São Paulo, SP, Brazil.
authors.forename: Rosana F
authors.initials: RF
authors.lastname: Romão-Corrêa
authors.forename: Durvanei A
authors.initials: DA
authors.lastname: Maria
authors.forename: Mithitaka
authors.initials: M
authors.lastname: Soma
authors.forename: Mírian N
authors.initials: MN
authors.lastname: Sotto
authors.forename: José Antônio
authors.initials: JA
authors.lastname: Sanches
authors.forename: Cyro Festa
authors.initials: CF
authors.lastname: Neto
authors.forename: Itamar R G
authors.initials: IR
authors.lastname: Ruiz
mesh_terms: D002280:Basal Cell Carcinoma / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D009697:Nucleolus Organizer Region / Q000378:metabolism* / Q000648:ultrastructure; D016612:Paraffin Embedding; D011230:Precancerous Conditions / Q000378:metabolism* / Q000473:pathology; D016622:Silver Staining; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure