Frequency of polymorphisms and protein expression of cyclin-dependent kinase inhibitor 1A (CDKN1A) in central nervous system tumors.
OBJECTIVE
Genetic investigation of central nervous system (CNS) tumors provides valuable information about the genes regulating proliferation, differentiation, angiogenesis, migration and apoptosis in the CNS. The aim of our study was to determine the prevalence of genetic polymorphisms (codon 31 and 3' untranslated region, 3'UTR) and protein expression of the cyclin-dependent kinase inhibitor 1A (CDKN1A) gene in patients with and without CNS tumors.


METHODS
Analytical cross-sectional study with a control group, at the Molecular Biology Laboratory, Pediatric Oncology Department, Hospital das Clínicas de Ribeirão Preto.


METHODS
41 patients with CNS tumors and a control group of 161 subjects without cancer and paires for sex, age and ethnicity were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Protein analysis was performed on 36 patients with CNS tumors, using the Western Blotting technique.


RESULTS
The frequencies of the heterozygote (Ser/Arg) and polymorphic homozygote (Arg/Arg) genotypes of codon 31 in the control subjects were 28.0% and 1.2%, respectively. However, the 3'UTR site presented frequencies of 24.2% (C/T) and 0.6% (T/T). These frequencies were not statistically different (P > 0.05) from those seen in the patients with CNS tumors (19.4% and 0.0%, codon 31; 15.8% and 2.6%, 3'UTR site). Regarding the protein expression in ependymomas, 66.67% did not express the protein CDKN1A. The results for medulloblastomas and astrocytomas were similar: neither of them expressed the protein (57.14% and 61.54%, respectively).


CONCLUSIONS
No significant differences in protein expression patterns or polymorphisms of CDKN1A in relation to the three types of CNS tumors were observed among Brazilian subjects.
Valentin
Mev Dominguez
MD
Genomic and Molecular Laboratory, Research Center, Hospital A. C. Camargo, São Paulo, Brazil. mev_dv@yahoo.com
Canalle
Renata
R
Queiroz
Rosane de Paula
Rde P
Tone
Luiz Gonzaga
LG
D020413:3' Untranslated Regions / Q000235:genetics; D000293:Adolescent; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003062:Codon / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics* / Q000378:metabolism; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*; D055815:Young Adult
D020413:3' Untranslated Regions; C493956:CDKN1A protein, human; D003062:Codon; D050759:Cyclin-Dependent Kinase Inhibitor p21; D009363:Neoplasm Proteins