Breast cancer is a complex heterogeneous disease involving genetic and epigenetic alterations in genes encoding proteins that are components of various signaling pathways. Candidate gene approach have identified association of genetic variants in the Wnt signaling pathway genes and increased susceptibility to several diseases including breast cancer. Due to the rarity of somatic mutations in key genes of Wnt pathway, we investigated the association of genetic variants in these genes with predisposition to breast cancers. We performed a case-control study to identify risk variants by examining 15 SNPs located in 8 genes associated with Wnt signaling. Genotypic analysis of individual locus showed statistically significant association of five SNPs located in β-catenin, AXIN2, DKK3, SFRP3 and TCF7L2 with breast cancers. Increased risk was observed only with the SNP in β-catenin while the other four SNPs conferred protection against breast cancers. Majority of these associations persisted after stratification of the cases based on estrogen receptor status and age of on-set of breast cancer. The rs7775 SNP in exon 6 of SFRP3 gene that codes for either arginine or glycine exhibited very strong association with breast cancer, even after Bonferroni's correction. Apart from these five variants, rs3923086 in AXIN2 and rs3763511 in DKK4 that did not show any association in the overall population were significantly associated with early on-set and estrogen receptor negative breast cancers, respectively. This is the first study to utilize pathway based approach to identify association of risk variants in the Wnt signaling pathway genes with breast cancers. Confirmation of our findings in larger populations of different ethnicities would provide evidence for the role of Wnt pathway as well as screening markers for early detection of breast carcinomas.

DNA repair is one of the central defense mechanisms against mutagenic exposures. Inherited SNPs of DNA repair genes may contribute to variations in DNA repair capacity and susceptibility to cancer. Due to the presence of these variants, inter-individual and ethnic diff erences in DNA repair capacity have been established in various populations. Saudi Arabia harbors enormous genetic and cultural diversity. In the present study we aimed to determine the genotype and allele frequencies of XRCC1 Arg399Gln (rs25487), XRCC3 Thr241Met (rs861539), XPD Lys751Gln (rs13181), and OGG1 Ser326Cys (rs1052133) gene polymorphisms in 386 healthy individuals residing in the central region of Saudi Arabia and compare them with HapMap and other populations. The genotype and allele frequencies of the four DNA repair gene loci in central Saudi population showed a distinctive pattern. Furthermore, comparison of polymorphisms in these genes with other populations also showed a unique pattern for the central Saudi population. To the best of our knowledge, this is the fi rst report that deals with these DNA repair gene polymorphisms among the central Saudi population.

Breast cancer (BC) is the most common cause of cancer-related deaths among women in the Kingdom of Saudi Arabia. An association between the dysregulation of innate immunity, primarily the deregulation of Toll-like receptors (TLRs), and BC development was described a long time ago. Several studies have reported that BC risk factors appear to be related to the interaction between certain genes and exposure to various environmental factors. Here, we investigated the potential correlation of three TLR2 single-nucleotide polymorphisms (SNPs; rs3804100, rs4696480, and rs3804099) with the development of BC in female patients from Saudi Arabia. We collected 126 blood samples from women with BC and 146 blood samples from healthy women without any clinical signs of BC. The genotypic frequencies of TLR2 polymorphisms were assayed. Our results showed that the genotypic and allelic frequencies of TLR2 did not differ significantly between BC patients and healthy controls. However, the distributions of rs3804100 (1350 T/C) genotypes in BC groups were 1%, 19%, and 80% for CC, CT, and TT, respectively. In the control group, the rs3804100 (1350 T/C) genotype distributions were 3%, 18%, and 79% for CC, CT, and TT, respectively. The SNP rs3804100 homozygous “TT” genotype was not associated with the risk of developing BC in the BC patients compared with controls (odds ratio [OR], 4.5; confidence interval [CI], 0.49–41.02; P=0.145). The TLR2 rs4696480 AA genotype was observed in 23% of BC patients compared to 18% of control individuals, the AT genotype was seen in 40% of BC patients and 46% of control individuals, and the TT genotype was observed in 37% of BC patients and 36% of normal controls. Our results did not show any difference in genotypic frequency between BC patients and normal controls for the TLR2 rs3804099 SNP; however, the (C) phenotypic frequency was 49% in BC patients and 53% in controls. The (T) phenotypic frequency was 51% and 47% in BC patients and normal patients, respectively. These findings indicate that there is no association between the TLR2 polymorphisms tested and BC susceptibility in the female population from the Kingdom of Saudi Arabia. We suggest using other TLR2 SNPs to investigate the possible relationship between innate immunity deregulation by disruption of TLR2 and potential BC development.

ABSTRACT. Abnormalities in the breast cancer tumor suppressor genes (BRCA1 and BRCA2) are associated with breast and ovarian cancer. Recently, two single nucleotide polymorphisms (SNPs; rs11571836 and rs1799943) were identified, both located in untranslated regions of chromosome 13, associated with cardiovascular disease (CVD) in a multi-ethnic population. We examined the association between these BRCA2 polymorphisms and traits of CVD patients from Saudi Arabia. We genotyped rs11571836 and rs1799943 in 159 unrelated CVD patients and 176 healthy controls. The genotype and allele distributions in the overall population revealed a statistically significant association between rs1799943 and CVD (P = 0.01-0.022), whereas no risk association was identified for rs11571836. Additionally, haplotype analysis using both SNPs demonstrated no association between the SNPs and CVD. The genotype distribution of the 2 SNPs in the normal Saudi population deviated significantly (P < 0.000001) from that of the 6 different HapMap populations (CEU, CHB-Han, JPT, YRI, GIH, and MKK), except for the JPT population for rs1799943. This is the BRCA2 variants and cardiovascular disease first study to examine the association between these SNPs and CVD in a Saudi population. Our results suggest that the increased health risk associated with the rs11571836 genotype is specific to male patients suffering from CVD. Stratification of patients and controls based on gender revealed no association between rs1799943 and the risk of CVD in either gender. These SNPs should be evaluated in larger cohorts in different populations to determine their suitability as screening markers for predicting CVD risk earlier in life to implement necessary preventive measures.

Objectives: Alternations in the estrogen receptor alpha gene (ERα) play an essential role in osteoporosis etiology. In this study, the relationship between a single nucleotide polymorphism (SNP) in ERα (G2014A) and osteoporosis in Saudi women were investigated. Methods:In this research 40 females with osteoporosis and 41 healthy controls ranging in age from 35 to 75 years were examined. Demographic data were recorded, and blood samples were drawn in plain and in EDTA tubes for estimation of estrogens in the serum and extraction of DNA, respectively. The DNA was used to amplify the fragment of interest carrying the SNP in ERα by polymerase chain reaction (PCR). The PCR product was subjected to DNA sequencing.Results: G2014A was polymorphic in Saudi women. Genotypes and allele frequencies were compared in the osteoporotic and non-osteoporotic groups. Although the genotypes of osteoporotic and non-osteoporotic subjects were significantly different (p=0.0157), the allelic frequency was not significantly different (p=0.519). Estrogen levels significantly differed between osteoporotic and nonosteoporotic subjects (mean ± SD E2: 46.6 ± 30.7 vs. 68.7 ± 47.1 pg/mL, p=0.0143). Importantly, a significant difference in waist-hip ratio in osteoporotic patient and the nonosteoporotic group was detected (0.8 ± 0.1 vs. 0.9 ± 0.0, p=0.0174). Conclusion:Although there was no relationship between G2014A and osteoporosis in Saudi women, this study sheds light on another aspect, such as the significant difference in estrogen levels in these two groups. Furthermore, an advantageous effect of fat on bone mass was observed in the non-osteoporotic group.