title: Genetic profile of adenoid cystic carcinomas (ACC) with high-grade transformation versus solid type.
abstract: BACKGROUND
  ACC can occasionally undergo dedifferentiation also referred to as high-grade transformation (ACC-HGT). However, ACC-HGT can also undergo transformation to adenocarcinomas which are not poorly differentiated. ACC-HGT is generally considered to be an aggressive variant of ACC, even more than solid ACC. This study was aimed to describe the genetic changes of ACC-HGT in relation to clinico-pathological features, and to compare results to solid ACC.
  
  
  METHODS
  Genome wide DNA copy number changes were analyzed by microarray CGH in ACC-HGT, four with transformation into moderately differentiated adenocarcinoma (MDA) and two into poorly differentiated carcinoma (PDC), and five solid ACC. In addition, Ki67 index and p53 immunopositivity was assessed.
  
  
  RESULTS
  ACC-HGT carried fewer copy number changes compared to solid ACC. Two ACC-HGT cases harboured a breakpoint at 6q23, near the cMYB oncogene. The complexity of the genomic profile concurred with the clinical course of the patient. Among the ACC-HGT, p53 positivity significantly increased from the conventional to the transformed (both MDA and PDC) component.
  
  
  CONCLUSIONS
  ACC-HGT may not necessarily reflect a more advanced stage of tumor progression, but rather a transformation to another histological form in which the poorly differentiated forms (PDC) presents a genetic complexity similar to the solid ACC.
authors.affiliation: Department of Pathology, University of Campinas/UNICAMP, Brazil. costa.anaflavia@gmail.com
authors.forename: Ana Flávia
authors.initials: AF
authors.lastname: Costa
authors.forename: Albina
authors.initials: A
authors.lastname: Altemani
authors.forename: Hedy
authors.initials: H
authors.lastname: Vékony
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bloemena
authors.forename: Florentino
authors.initials: F
authors.lastname: Fresno
authors.forename: Carlos
authors.initials: C
authors.lastname: Suárez
authors.forename: José Luis
authors.initials: JL
authors.lastname: Llorente
authors.forename: Mario
authors.initials: M
authors.lastname: Hermsen
mesh_terms: D000199:Actins / Q000378:metabolism; D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D003528:Carcinoma, Adenoid Cystic / Q000235:genetics* / Q000473:pathology; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics; D055028:Comparative Genomic Hybridization; D056915:DNA Copy Number Variations / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: D000199:Actins; D019394:Ki-67 Antigen