br Combined genotypes were evaluated as genotypes combinatio
Combined genotypes were evaluated as genotypes combination of these two polymorphisms. A total of 9 combinations were studied and as shown in Table 3, the combination of Arg/Arg in WRAP53 and Arg/ Arg in TP53 were the most frequent combination in both cases and controls.
Pairwise haplotype estimation was carried out by Haploview V4.2. The haplotype analysis revealed the statistically significant distribution of the G allele (Gly) in BAY-598 68 of WRAP53 with the C allele (Pro) in codon 72 of TP53 which makes GC haplotype with a p-value of 0.024 and it is in close relationship with breast cancer susceptibility in this population (Table 4). Furthermore, linkage disequilibrium estimation with D′ = 0.324 and r2 = 0.037 doesn't show strong LD between these two SNPs (Fig. 1).
In silico analysis for each SNP by bioinformatics online software are shown in Table 5 and Fig. 2.
In response to the urge of finding polymorphism eﬀects in sus-ceptibility to malignancies, many studies have been conducted to elu-cidate the impacts. Among various polymorphisms, Arg72Pro sub-stitution in TP53 has been studied the most. In Osorio et al. and Cavallone et al. works, this SNP has proven to be linked with breast
cancer (Osorio et al., 2008; Cavallone et al., 2008) and Wilms tumor (Fu et al., 2017) but two other experiments didn't find any relevant pre-disposition to thyroid (Dehghan et al., 2015) and breast cancers (Sinilnikova et al., 2009). Our results were not consistent with Osorio et al. and Cavallone et al. and didn't show any significant association with breast cancer predisposition among our assessed population. Be-sides, based on meta-analysis the association of this SNP with colorectal cancer (Tian et al., 2017) lack of association with ovarian cancer (Zhang et al., 2017) have been elucidated.
In terms of WRAP53 polymorphism, Arg68Gly substitution has been studied in diﬀerent populations. In the Polish population with 626 cases and 1045 healthy women, the association between ovarian cancer and this SNP have been revealed (Medrek et al., 2013). In two large case-control populations evaluated for the relationship between WRAP53 and TP53 polymorphism with breast cancer predisposition, the rs2287499 from WRAP53 suggested could have an association with ER-negative breast cancers (Garcia-Closas et al., 2007). This SNP has also been proven to be linked with breast cancer (Cao et al., 2016) but our results were not in concordance with these works.
In this study, we evaluated the codon 72 of TP53 and codon 68 of WRAP53 polymorphisms with the risk of breast cancer. Also, we in-vestigated the pairwise and combined genotypes in the population. Based on our results, there was no significant association between polymorphisms of our interest in TP53 and WRAP53 with breast cancer susceptibility. Furthermore, by evaluating the clinicopathological manifestations with these genetic variations, we found a significant correlation between TP53 SNP and the size of the tumor with the p-value of 0.038.
Moreover, the combined genotype of Arg/Arg in codon 68 of WRAP53 and Arg/Arg in codon 72 of TP53 were the most frequent in both cases and controls but didn't show any significant relations.
N. Pouladi et al.
5.2. Haplotype analysis
To our notion, there was no previously reported investigation to imply the relation of haplotype including rs2287499 and rs1042522 with the increased risk of cancer (Jung et al., 2008) (Alonso et al., 2010), to be the first one, our pairwise analysis showed that haplotype of GC, with Gly in codon 68 of WRAP53 and Pro in codon 72 of TP53, is related to breast cancer susceptibility in this population with p-value being 0.024. Why this haplotype influence this population predisposi-tion to breast cancer is not clear and to find out further studies need to be done in genomic and molecular level as well as large population-based association studies.
In 2009, Santos Alonso et al. reported D′ = 0.48 between rs2287499 and rs1042522 which indicated a moderate LD in Caucasians (Alonso et al., 2010). In concordance with their results, as shown in Fig. 1, the LD estimation between these two markers in our population doesn't show strong linkage disequilibrium with D′ being 0.32. Furthermore, similar to the degree estimated by Xingqun Ni et al. in which for Tor-onto population was 28 and for Portuguese population was 35, it didn't confer relation between these SNPs and schizophrenia in the assessed populations (Ni et al., 2005). This result shows that this population doesn't have homogeneity for these markers and for deeper investiga-tions more markers flanking these two, should be genotype and analyze for linkage disequilibrium.