Genetic profile of adenoid cystic carcinomas (ACC) with high-grade transformation versus solid type.
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, 4 with transformation into moderately differentiated adenocarcinoma (MDA) and two into poorly differentiated carcinoma (PDC), 5 solid ACC. In addition, Ki-67 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.
Costa
Ana Flávia
AF
Department of Pathology, University of Campinas/UNICAMP, Campinas, Brazil. costa.anaflavia@gmail.com
Altemani
Albina
A
Vékony
Hedy
H
Bloemena
Elisabeth
E
Fresno
Florentino
F
Suárez
Carlos
C
Llorente
José Luis
JL
Hermsen
Mario
M
D000328:Adult; D000368:Aged; D003528:Carcinoma, Adenoid Cystic / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D002454:Cell Differentiation / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology*; D055028:Comparative Genomic Hybridization; D005260:Female; D018628:Gene Dosage; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000235:genetics; D008297:Male; D042282:Microdissection; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53