MYC insertions in diffuse-type gastric adenocarcinoma.
BACKGROUND
MYC is important in gastric carcinogenesis. A few studies reported MYC translocation or insertion associated with gastric cancer.


METHODS
MYC copy number and its insertion, as well as the chromosomes in which MYC was inserted, were evaluated by fluorescence in situ hybridization assay in interphase and metaphase cells of 12 diffuse-type gastric cancer samples. MYC protein expression was evaluated by immunohistochemistry.


RESULTS
The presence of 3 MYC signals was the most frequent alteration. All cases also presented 4 and 5 MYC signals. In all samples, we observed chromosome 8 trisomy with MYC copies and MYC insertion into the chromosomes 2, 7, 14, 17, 18 and 22. All samples presented nucleic and cytoplasmic immunoreactivity.


CONCLUSIONS
MYC cytoplasmic immunoreactivity can be the result of MYC insertion with the breakpoints within or close to the regions that are able to target the nucleus. MYC insertion and cytoplasmatic immunoreactivity may be a common characteristic of diffuse-type gastric cancer.
Calcagno
Danielle Queiroz
DQ
Human Cytogenetics Laboratory, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil.
Guimarães
Adriana Costa
AC
Leal
Mariana Ferreira
MF
Seabra
Aline Damaceno
AD
Khayat
André Salim
AS
Pontes
Thais Brilhante
TB
Assumpção
Paulo Pimentel
PP
De Arruda Cardoso Smith
Marília
M
Burbano
Rommel Rodríguez
RR
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000368:Aged; D002898:Chromosomes, Human, Pair 8; D018628:Gene Dosage; D016259:Genes, myc; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D008677:Metaphase; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D014314:Trisomy