ORIGINAL PAPER Genetic profile of adenoid cystic carcinomas (ACC) with high-grade transformation versus solid type Ana Flávia Costa & Albina Altemani & Hedy Vékony & Elisabeth Bloemena & Florentino Fresno & Carlos Suárez & José Luis Llorente & Mario Hermsen Accepted: 19 September 2010 / Published online: 4 May 2011 # International Society for Cellular Oncology 2011 Abstract Background ACC can occasionally undergo dedifferentia- tion also referred to as high-grade transformation (ACC- HGT). However, ACC-HGT can also undergo transforma- tion to adenocarcinomas which are not poorly differentiat- ed. 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 adenocarcino- ma (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. Conclusion ACC-HGT may not necessarily reflect a more advanced stage of tumor progression, but rather a transfor- mation to another histological form in which the poorly differentiated forms (PDC) presents a genetic complexity similar to the solid ACC. Keywords Adenoid cystic carcinoma . High-grade transformation . Dedifferentiation . Microarray CGH 1 Introduction Adenoid cystic carcinoma is a slow-growing tumor pre- senting a dual cellular composition, i.e., ductal (luminal) and myoepithelial cell differentiation and three major growth patterns: tubular, cribriform and solid [1]. The solid growth pattern has been considered to be an adverse prognosticator [2–4] and in a three-tired system for grading ACC, tumors having more than 30% of the solid compo- nent are classified as grade III or poorly differentiated. This paper is a reprint from ‘Genetic profile of adenoid cystic carcinomas (ACC) with high-grade transformation versus solid type, Ana Flávia Costa, Albina Altemani, Hedy Vékony, Elisabeth Bloemena, Florentino Fresno, Carlos Suárez, José Luis Llorente, Mario Hermsen’ originally published in Analytical Cellular Pathology/Cellular Oncology, Volume 33, number 5–6, 2010, pp. 217–228, IOS Press. A. F. Costa : A. Altemani Department of Pathology, University of Campinas/UNICAMP, Campinas, Brazil H. Vékony : E. Bloemena Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands F. Fresno Department of Pathology, IUOPA, Hospital Universitario Central de Asturias, Oviedo, Spain C. Suárez : J. L. Llorente : M. Hermsen Department of Otolaryngology, IUOPA, Hospital Universitario Central de Asturias, Oviedo, Spain A. F. Costa (*) Departamento de Anatomia Patológica, Faculdade de Ciências Médicas, UNICAMP, Rua Tessália Vieira de Camargo 126, ZIP Code 13084-971 Campinas, São Paulo, Brazil e-mail: costa.anaflavia@gmail.com Cell Oncol. (2011) 34:369–379 DOI 10.1007/s13402-011-0037-5