Hereditary breast cancer in Middle Eastern and North African (MENA) populations: identification of novel, recurrent and founder BRCA1 mutations in the Tunisian population

Germ-line mutations in BRCA1 breast cancer susceptibility gene account for a large proportion of hereditary breast cancer families and show considerable ethnic and geographical variations. The contribution of BRCA1 mutations to hereditary breast cancer has not yet been thoroughly investigated in Middle Eastern and North African populations. In this study, 16 Tunisian high-risk breast cancer families were screened for germline mutations in the entire BRCA1 coding region and exon–intron boundaries using direct sequencing. Six families were found to carry BRCA1 mutations with a prevalence of 37.5%. Four different deleterious mutations were detected. Three truncating mutations were previously described: c.798_799delTT (916 delTT), c.3331_3334delCAAG (3450 delCAAG), c.5266dupC (5382 insC) and one splice site mutation which seems to be specific to the Tunisian population: c.212 + 2insG (IVS5 + 2insG). We also identified 15 variants of unknown clinical significance. The c.798_799delTT mutation occurred at an 18% frequency and was shared by three apparently unrelated families. Analyzing five microsatellite markers in and flanking the BRCA1 locus showed a common haplotype associated with this mutation. This suggests that the c.798_799delTT mutation is a Tunisian founder mutation. Our findings indicate that the Tunisian population has a spectrum of prevalent BRCA1 mutations, some of which appear as recurrent and founding mutations

ACC interleukin-10 gene promoter haplotype as a breast cancer risk factor predictor among Jordanian females

Manar Fayiz Atoum Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, Zarqa, Jordan Introduction: Interleukin-10 (IL-10) is a multifactorial cytokine with a complex biological role in breast cancer. The aims of this study were to investigate any association between IL-10 gene promoter polymorphisms, 1082A>/G, -819T>C, and -592A>C, or haplotypes and breast cancer risk among Jordanian women and to evaluate any association between the most common haplotype with clinicopathological features of breast cancer.Patients and methods: A total of 202 breast cancer patients and 210 age-matched healthy control subjects were genotyped for -1082A/G, -819T/C, and -592A/C single nucleotide polymorphisms in the promoter region of the IL-10 gene by polymerase chain reaction-restriction fragment length polymorphism. Study patients and control subjects were recruited from Prince Hamzah Hospital, Amman, Jordan (2012–2013). Ethical approval and signed consent forms were signed by all participants. DNA was extracted, and polymerase chain reaction fragments were amplified and restriction digested by MnII, MaeIII, and RsaI.Results: This study showed no statistically significant difference between -1082A/G, -819T/C, and -592A/C IL-10 genotypes or alleles among breast cancer patients or controls. Four different haplotypes ATA, ACC, GTA, and ACA within the IL-10 promoter gene were determined among both breast cancer and control groups. The most frequent haplotype was ACC among breast cancer patients and controls (41.6% and 40.7%, respectively). No statistical differences in these haplotypes among breast cancer patients or controls were determined. Analysis of the most common ACC haplotype showed statistical difference in positive estrogen receptor (P=0.022), positive progesterone receptor (P=0.004), cancer grade (P=0.0001), and cancer stage (P=0.009) among the ACC haplotype compared to non-ACC haplotype.Conclusion: To our knowledge, this is the first report studying the association of IL-10 haplotype with breast cancer risk events among Jordanian females. The most frequent IL-10 haplotype among Jordanian breast cancer females is ACC haplotype. Patients carrying the ACC haplotype are associated with higher positive estrogen and progesterone receptors and advanced breast cancer grade and stage. These patients also had lower survival rate in the Kaplan–Meier survival plot compared to those with non-ACC haplotype. Keywords: interleukin-10, genotypes, haplotypes, breast cance

Reduction in breast cancer susceptibility due to XbaI gene polymorphism of alpha estrogen receptor gene in Jordanians

Manar Fayiz Atoum, Foad Alzoughool Department of Medical Laboratory Sciences, Faculty of Allied Health, Hashemite University, Zarqa, Jordan Abstract: Breast cancer is a global health concern among women worldwide. Estrogen receptor alpha (ERα) mediates diverse polymorphic effects in breast tissues that may relate to breast cancer susceptibility. The aim of this study was to evaluate the effect of −397 PvuII (T/C) and −351 XbaI (A/G) restriction fragment length polymorphism within intron 1 of ERα, and its effect on breast cancer susceptibility. A total of 156 women who were histopathologically diagnosed with breast cancer and 142 healthy Jordanian women were enrolled in this case–control study. Genomic DNA was extracted from whole peripheral blood, and the desired fragment was amplified using polymerase chain reaction followed by restriction digestion with PvuII and XbaI restriction enzymes. The results showed no significant association between PvuII polymorphism and breast cancer risk. However, a significant association was found between XbaI polymorphism and reduction in breast cancer risk within the “x” allele of heterozygotes (odds ratio [OR] 0.199, 95% confidence interval [CI] 0.09–0.044) and heterozygotes (OR 0.208, 95% CI 0.09–0.047). The combined analysis of PvuII and XbaI polymorphisms revealed a synergistic effect of Pp/Xx and pp/xx genotypes and a significant reduction in breast cancer risk with these genotypes. The results also showed no statistical differences among PvuII or XbaI polymorphisms based on stage, ER, progesterone receptor and expression of hormone receptor such as human epidermal growth factor receptor 2. This case–control study showed that XbaI polymorphism of alpha estrogen gene modified and reduced breast cancer susceptibility among Jordanians. Keywords: breast cancer, gene polymorphism, Xba