Interrelationship between TP53 gene deletion, protein expression and chromosome 17 aneusomy in gastric adenocarcinoma.
BACKGROUND
This study evaluates the existence of numerical alterations of chromosome 17 and TP53 gene deletion in gastric adenocarcinoma. The p53 protein expression was also evaluated, as well as, possible associations with clinicopathological characteristics.


METHODS
Dual-color fluorescence in situ hybridization and immunostaining were performed in twenty gastric cancer samples of individuals from Northern Brazil.


RESULTS
Deletion of TP53 was found in all samples. TP53 was inactivated mainly by single allelic deletion, varying to 7-39% of cells/case. Aneusomy of chromosome 17 was observed in 85% of cases. Chromosome 17 monosomy and gain were both observed in about half of cases. Cells with gain of chromosome 17 frequently presented TP53 deletion. The frequency of cells with two chr17 and one TP53 signals observed was higher in diffuse than in intestinal-type GC. Immunoreactivity of p53 was found only in intestinal-type samples. The frequency of cells with two chr17 and two TP53 signals found was higher in samples with positive p53 expression than in negative cases in intestinal-type GC.


CONCLUSIONS
We suggest that TP53 deletion and chromosome 17 aneusomy is a common event in GC and other TP53 alterations, as mutation, may be implicated in the distinct carcinogenesis process of diffuse and intestinal types.
Khayat
André S
AS
Human's Cytogenetics Laboratory, Institute of Biological Sciences, Federal University of Pará, Av Augusto Correa 01, 66075-900, Belém, PA, Brazil. khayatas@gmail.com
Guimarães
Adriana C
AC
Calcagno
Danielle Q
DQ
Seabra
Aline D
AD
Lima
Eleonidas M
EM
Leal
Mariana F
MF
Faria
Mário H G
MH
Rabenhorst
Silvia H B
SH
Assumpção
Paulo P
PP
Demachki
Samia
S
Smith
Marília A C
MA
Burbano
Rommel R
RR
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000483:Alleles; D001938:Brazil; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D019656:Loss of Heterozygosity / Q000235:genetics; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
D016159:Tumor Suppressor Protein p53