Our results thus suggest that the CASP8 5'-UTR C > T are associated with breast cancer risks and the effect may be modified by estrogen and progesterone receptor status.
The reproducible, dose-dependent association of CASP8D302H with breast cancer indicates the potential importance of inherited variation in the apoptosis pathway in breast cancer susceptibility.
Five miRNA binding site SNPs associated significantly with breast cancer risk: rs1045494 (odds ratio (OR) 0.92; 95% confidence interval (CI): 0.88-0.96), rs1052532 (OR 0.97; 95% CI: 0.95-0.99), rs10719 (OR 0.97; 95% CI: 0.94-0.99), rs4687554 (OR 0.97; 95% CI: 0.95-0.99, and rs3134615 (OR 1.03; 95% CI: 1.01-1.05) located in the 3' UTR of CASP8, HDDC3, DROSHA, MUSTN1, and MYCL1, respectively.
In conclusion, the result suggests that the CASP8 -652 6N del polymorphism plays a protective role in susceptibility to breast cancer in our population.
In multivariate analyses, we observed a significantly decreased risk of breast cancer associated with the homozygous minor allele of CASP8D302H [rs1045485, odds ratio (OR), 0.3; 95% confidence interval (95% CI), 0.1-0.8].
The minor allele of CASP8D302H was significantly associated with a reduced risk of breast cancer (per-allele HR, 0.85; 95% CI, 0.76-0.97; P(trend) = 0.011) and ovarian cancer (per-allele HR, 0.69; 95% CI, 0.53-0.89; P(trend) = 0.004) for BRCA1 but not for BRCA2 mutation carriers.
Consistent with their breast cancer associations, rs3817198 (LSP1) and rs13281615 (8q) were associated with dense area and percent dense area (all P(x) and P(c) <0.05), and rs889312 (MAP3K1), rs2107425 (H19), and rs17468277 (CASP8) were marginally associated with dense area (some P(x) or P(c) <0.05).
We found evidence of an association with breast cancer for CASP8D302H (with odds ratios (OR) of 0.89 (95% confidence interval (c.i.): 0.85-0.94) and 0.74 (95% c.i.
Our results indicate that genetic variations in the promoter region of CASP8 gene, especially rs3834129, may serve as a genetic risk factor for breast cancer in an Iranian population.
In order to further map the CASP8 gene with respect to breast cancer susceptibility, we performed extensive haplotype analyses using single nucleotide polymorphisms (SNP) chosen to tag all common variations in the gene (tSNP).
As CASP10 and CASP8 functionally co-operate during apoptosis, we analysed the mutual effect of both CASP10 V410I and CASP8D302H, resulting in a significant association between the number of the variant alleles I410 and H302 and a highly decreased familial BC risk (OR = 0.35, P(trend) = 0.007), pointing to the interaction between the CASP10 and CASP8 polymorphisms in breast carcinogenesis.
Because of the lack of studies concerning the 2 common polymorphisms in caspase 8 (CASP8), namely rs104548 and rs10931936 in Iranian population, we evaluated the association of these 2 polymorphisms and their haplotypes with breast cancer and molecular profile.
We also identified a known breast cancer locus CASP8/ALS2CR12 associated with prostate cancer, a known cancer locus at CDKN2B-AS1 with different variants associated with lung adenocarcinoma and prostate cancer, and confirmed the associations of a breast BRCA2 locus with lung and serous ovarian cancer.
Here, we show that the rs700635[C] allele, which is associated with increased risk of BCC and breast cancer, is protective against prostate cancer [odds ratio (OR) = 0.91, P = 1.0 × 10(-6)]. rs700635[C] is also associated with failures to correctly splice out CASP8 intron 8 in breast and prostate tumours and in corresponding normal tissues.
Confirmed BC risk SNPs rs17468277 (CASP8), rs1982073 (TGFB1), rs2981582 (FGFR2), rs13281615 (8q24), rs3817198 (LSP1), rs889312 (MAP3K1), rs3803662 (TOX3), rs13387042 (2q35), rs4973768 (SLC4A7), rs6504950 (COX11) and rs10941679 (5p12) were genotyped for 25 853 BC patients with the available follow-up; 62 other SNPs, which have been suggested as BC risk SNPs by a GWAS or as candidate SNPs from individual studies, were genotyped for replication purposes in subsets of these patients.
Ten SNPs (rs2075555 in COL1A1, rs12652447 in FBXL17, rs10941679 in 5p12/MRPS30, rs11878583 in ZNF577, rs7166081 in SMAD3, rs16917302 in ZNF365, rs311499 in 20q13.3, rs1045485 in CASP8, rs12964873 in CDH1 and rs8170 in 19p13.1) were here genotyped in 1009 Chinese females (487 patients with breast cancer and 522 control subjects) using the Sequenom MassARRAY iPLEX platform.
A dose-dependent association was observed between the risk of breast cancer and the genetic risk score, which was an aggregate measure of alleles in seven selected variants, namely FGFR2-rs2981579, TOX3/TNRC9-rs3803662, C6orf97-rs2046210, 8q24-rs13281615, SLC4A7-rs4973768, LSP1-rs38137198, and CASP8-rs10931936.
Polymorphisms in CASP8 at 2q33.1 have been associated with the risk of developing cancer, specifically, the D302H variant (rs1045485) with breast cancer in the European population and the -652 6N ins/del promoter variant (rs3834129) with multiple tumours including colorectal cancer (CRC) in the Chinese population.
Recent work from large consortial studies has led to the discovery of novel breast cancer susceptibility loci in genic (CASP8, FGFR2, TNRC9, MAP3K1, LSP1) and nongenic regions (8q24, 2q35, 5p12) of the genome, and to the finding of substantial heterogeneity by tumor characteristics.