Interrelationship between chromosome 8 aneuploidy, C-MYC amplification and increased expression in individuals from northern Brazil with gastric adenocarcinoma.
OBJECTIVE
To investigate chromosome 8 numerical aberrations, C-MYC oncogene alterations and its expression in gastric cancer and to correlate these findings with histopathological characteristics of gastric tumors.


METHODS
Specimens were collected surgically from seven patients with gastric adenocarcinomas. Immunostaining for C-MYC and dual-color fluorescence in situ hybridization (FISH) for C-MYC gene and chromosome 8 centromere were performed.


RESULTS
All the cases showed chromosome 8 aneuploidy and C-MYC amplification, in both the diffuse and intestinal histopathological types of Lauren. No significant difference (P < 0.05) was observed between the level of chromosome 8 ploidy and the site, stage or histological type of the adenocarcinomas. C-MYC high amplification, like homogeneously stained regions (HSRs) and double minutes (DMs), was observed only in the intestinal-type. Structural rearrangement of C-MYC, like translocation, was observed only in the diffuse type. Regarding C-MYC gene, a significant difference (P < 0.05) was observed between the two histological types. The C-MYC protein was expressed in all the studied cases. In the intestinal-type the C-MYC immunoreactivity was localized only in the nucleus and in the diffuse type in the nucleus and cytoplasm.


CONCLUSIONS
Distinct patterns of alterations between intestinal and diffuse types of gastric tumors support the hypothesis that these types follow different genetic pathways.
Calcagno
Danielle-Queiroz
DQ
Human Cytogenetics and Toxicological Genetics Laboratory, Department of Biology, Center of Biological Sciences, Federal University of Pará, Belém, PA, Brazil.
Leal
Mariana-Ferreira
MF
Seabra
Aline-Damaceno
AD
Khayat
Andre-Salim
AS
Chen
Elizabeth Suchi
ES
Demachki
Samia
S
Assumpção
Paulo Pimentel
PP
Faria
Mario Henrique Girão
MH
Rabenhorst
Silvia Helena Barem
SH
Ferreira
Márcia Valéria Pitombeira
MV
de Arruda Cardoso Smith
Marília
M
Burbano
Rommel-Rodríguez
RR
D000230:Adenocarcinoma / Q000235:genetics*; D000328:Adult; D000368:Aged; D000782:Aneuploidy; D001938:Brazil; D002898:Chromosomes, Human, Pair 8; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000235:genetics*