Absence of CIP1/KIP1 hypermethylation in gastric cancer patients from Northern Brazil.
The aim of this study was to investigate the protein expression and methylation pattern of P21(CIP1) and P27(KIP1) genes.


METHODS
Twenty samples of gastric tumor and non-tumoral tissues of patients from Pará state, Brazil were collected. Methylation patterns were assessed by bisulfite sequencing, and protein expression evaluated with immunohistochemical analysis.


RESULTS
None of the analyzed samples showed methylation in both genes. Immunohistochemistry analysis demonstrated mislocalization or absence of expression of P21(CIP1) and P27(KIP1) in 7/20 and 6/20 of the studied samples, respectively. No correlations regarding protein expression and clinicopathological characteristics were observed; down-regulation of expression of P21(CIP1) with low (I-II) tumor stage (p=0.0777), and older age (>50 years old) with negative or mislocalization of P27(KIP1) (p=0.0922) were of borderline the statistical significance.


CONCLUSIONS
Our results suggest that hypermethylation does not contribute to P21(CIP1) and P27(KIP1) silencing in gastric cancer, and that the role of these genes in the gastric tumorigenesis pathways should be studied further in the Pará state population.
Do Nascimento Borges
Bárbara
B
Laboratório de Biologia Molecular 'Francisco Mauro Salzano', Instituto de Ciências Biológicas, Universidade Federal do Pará, R. Augusto Correa 01, 66075-110 Belém, Pará, Brazil. bnborges@ufpa.br
Burbano
Rommel Mario Rodriguez
RM
Harada
Maria Lúcia
ML
D000328:Adult; D000368:Aged; D001938:Brazil; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008745:Methylation; D008875:Middle Aged; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
C493956:CDKN1A protein, human; C436291:CDKN1B protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004273:DNA, Neoplasm; D047908:Intracellular Signaling Peptides and Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27