Beschreibung:
<jats:title>Abstract</jats:title><jats:p>We analysed the association of a single nucleotide polymorphism (SNP) in the gene encoding the IL‐12 subunit p40 (IL12B, rs3212227, A>C) with breast cancer. The SNPs allelic and genotypic frequencies were compared between patients (<jats:italic>n </jats:italic>= 191) and healthy (<jats:italic>n </jats:italic>= 194) women in a case–control study from Croatia. The major allele (A) was associated with susceptibility to breast cancer (<jats:italic>P </jats:italic>= 0.003; OR<jats:italic> </jats:italic>= 1.67; 95% CI: 1.17–2.38). Likewise, the minor allele (C) was significantly correlated with protection (<jats:italic>P </jats:italic>= 0.003; OR<jats:italic> </jats:italic>= 0.60; 95% CI: 0.42–0.86). At the genotype level, AA homozygosity was significantly associated with predisposition to disease (<jats:italic>P </jats:italic>= 0.013; OR<jats:italic> </jats:italic>= 1.68, 95% CI: 1.09–2.59), whereas the minor allele homozygosity (CC) was correlated with protection to disease (<jats:italic>P </jats:italic>= 0.020, OR<jats:italic> </jats:italic>= 0.28, 95% CI: 0.09–0.91). The heterozygous genotype showed no significant correlation with disease. The product of the IL12B gene (IL‐12 p40) can either form a homodimeric cytokine or be part of two pro‐inflammatory (IL‐12 and IL‐23) cytokines. It is presently unclear whether the major allele is associated with higher or lower protein levels of IL‐12 p40 and IL‐12 p70, which are critical in inflammation and adaptive immune responses. However, as the A allele is high producer of IL12B (p40) mRNA, these results might imply that higher levels of IL‐12 p40 (either as homodimers or joined with one or both of the other two subunits) predispose to breast cancer.</jats:p>