An miR-502-binding site single-nucleotide polymorphism in the 3'-untranslated region of the SET8 gene is associated with early age of breast cancer onset.
OBJECTIVE
MicroRNAs regulate gene expression by binding to the 3'-untranslated region (UTR) of target genes. Single-nucleotide polymorphisms of critical genes may affect their regulation by microRNAs. We have identified a single-nucleotide polymorphism within the miR-502 seed binding region in the 3'-UTR of the SET8 gene. SET8 methylates TP53 and regulates genome stability. We investigated the role of this SET8 single-nucleotide polymorphism and in concert with the TP53 codon 72 single-nucleotide polymorphism in the propensity for onset of breast cancer.


METHODS
We measured the SET8 single-nucleotide polymorphisms in a case-control study on 1,110 breast cancer cases and 1,097 controls.


RESULTS
The SET8 CC and TP53 GG genotypes were independently associated with an earlier age of breast cancer onset in an allele-dose-dependent manner (for SET8, 52.2 years for TT, 51.4 for TC, and 49.5 for CC; and for TP53, 53.1 years for CC, 51.5 for GC, 50.7 for GG). Individuals with combined SET8 CC and TP53 GG genotypes developed cancer at a median age of 47.7 years as compared with 54.6 years for individuals with combined SET8 TT and TP53 CC genotypes. In the 51 breast cancer tissue samples tested, the SET8 CC genotype was associated with reduced SET8, but not miR-502, transcript levels.


CONCLUSIONS
These data suggest that the miR-502-binding site single-nucleotide polymorphism in the 3'-UTR of SET8 modulates SET8 expression and contributes to the early development of breast cancer, either independently or together with the TP53 codon 72 single-nucleotide polymorphism. Larger studies with multiethnic groups are warranted to validate our findings.
Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Hospital and Institute, Tianjin, People's Republic of China.
Fengju
F
Song
Hong
H
Zheng
Ben
B
Liu
Sheng
S
Wei
Hongji
H
Dai
Lina
L
Zhang
George A
GA
Calin
Xishan
X
Hao
Qingyi
Q
Wei
Wei
W
Zhang
Kexin
K
Chen
D020413:3' Untranslated Regions / Q000235:genetics*; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
D020413:3' Untranslated Regions; C545730:MIRN502 microRNA, human; D035683:MicroRNAs; D011495:Histone-Lysine N-Methyltransferase; C470730:KMT5A protein, human