• Asian Pacific Journal of Cancer Prevention
• /
• 제15권24호
• /
• pp.10585-10589
• /
• 2015

Breast cancer susceptibility gene 1 (BRCA1), mapped on chromosome 17q21, is implicated in the mechanisms of cellular DNA repair. Inactivation of this gene is involved in the development of many human cancers, including breast cancer. This study aimed to investigate the prognostic value of BRCA1 promoter hypermethylation and expression in breast cancer cases. Sixty-one breast cancers were examined for BRCA1 hypermethylation by methylation-specific polymerase chain reaction (PCR), and 45 paired normal breast tissues were analyzed for altered BRCA1 mRNA levels by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Aberrant methylation status in BRCA1 was detected in 15 of 61 cases (24.6%), while reduced expression was found in 7 of 45 (15.6%). BRCA1 hypermethylation was statistically associated with tumor grade III (p=0.04), a high frequency of stage IIB (p=0.02), and triple-negative phenotype (OR= 3.64, 95%CI =1.1-12.3, p=0.03). Our findings indicated that BRCA1 promoter hypermethylation is a useful prognostic marker for breast cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권4호
• /
• pp.2199-2203
• /
• 2016

One of the most common cancer types faced by the women around the world is breast cancer. Among the several low, moderate and high penetrance genes conferring susceptibility to breast cancer, PTEN is one which is known to be mutated in many tumor types. In this study, we predicted and analyzed the impact of three deleterious coding non-synonymous single nucleotide polymorphisms rs121909218 (G129E), rs121909229 (R130Q) and rs57374291 (D107N) in the PTEN gene on the phenotype of breast tumors using computational tools SIFT, Polyphen-2, PROVEAN, MUPro, POPMusic and the GETAREA server.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권6호
• /
• pp.2231-2235
• /
• 2015

Genome-wide association studies (GWASs) of the entire genome provide a systematic approach for revealing novel genetic susceptibility loci for breast cancer. However, genetic association studies have hitherto been primarily conducted in women of European ancestry. Therefofre we here performed a pilot GWAS with a single nucleotide polymorphism (SNP) array 5.0 platform from $Affymetrix^{(R)}$ that contains 443,813 SNPs to search for new genetic risk factors in 89 breast cancer cases and 46 healthy women of Indonesian ancestry. The case-control association of the GWAS finding set was evaluated using PLINK. The strengths of allelic and genotypic associations were assessed using logistic regression analysis and reported as odds ratios (ORs) and P values; P values less than $1.00{\times}10^{-8}$ and $5.00{\times}10^{-5}$ were required for significant association and suggestive association, respectively. After analyzing 292,887 SNPs, we recognized 11 chromosome loci that possessed suggestive associations with breast cancer risk. Of these, however, there were only four chromosome loci with identified genes: chromosome 2p.12 with the CTNNA2 gene [Odds ratio (OR)=1.20, 95% confidence interval (CI)=1.13-1.33, $P=1.08{\times}10^{-7}$]; chromosome 18p11.2 with the SOGA2 gene (OR=1.32, 95%CI=1.17-1.44, $P=6.88{\times}10^{-6}$); chromosome 5q14.1 with the SSBP2 gene (OR=1.22, 95%CI=1.11-1.34, $P=4.00{\times}10^{-5}$); and chromosome 9q31.1 with the TEX10 gene (OR=1.24, 95%CI=1.12-1.35, $P=4.68{\times}10^{-5}$). This study identified 11 chromosome loci which exhibited suggestive associations with the risk of breast cancer among Indonesian women.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권4호
• /
• pp.1725-1727
• /
• 2016

Breast cancer contributes to approximately 23% of the cancer cases identified and 14% of cancer related deaths worldwide. Including a strong association between genetic and environmental factors, breast cancer is a complex and multi factorial disorder. Two high penetration breast cancer susceptibility genes (BRCA1 and BRCA2) have been identified, and germ line mutations in these are thought to account for between 5% and 10% of all breast cancer cases. The human BRCA1 gene, located on 17q, is involved in the regulation of cell proliferation by aiding in DNA repair, transcriptional responses to DNA damage and cell cycle check points. Mutations in this gene enhance cell proliferation and facilitate formation of tumors. Two mutations, the 185 deletion of AG and the 4627 substitution from C to A, are founder mutations in the BRCA1 gene for breast cancer in Asian populations. Allele specific PCR was performed to detect these selected mutations in 120 samples. No mutation of 4627 C to A was detected in the samples and only one of the patients had the 185 del AG mutation in the heterozygous condition. Our collected samples had lower consanguinity and family history indicating the greater involvement of environmental as compared to genetic factors.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권3호
• /
• pp.1133-1140
• /
• 2014

Altered DNA repair capacity can result in increased susceptibility to cancer. The base excision repair (BER) pathway effectively removes DNA damage caused by ionizing radiation and reactive oxidative species (ROS). In the current study, we analyzed the possible relation of polymorphisms in BER genes, including 8-oxoguanine DNA glycosylase (OGG1), apurinic/apyrimidinic endonuclease 1 (APE1), and X-ray repair cross-complementing group 1 protein (XRCC1), with breast cancer risk in Chinese Han women. This case-control study examined 194 patients with breast cancer and 245 cancer-free hospitalized control subjects. Single nucleotide polymorphisms (SNPs) of OGG1 (Ser326Cys), XRCC1 (Arg399Gln), and APE1 (Asp148Glu and -141T/G) were genotyped and analyzed for their association with breast cancer risk using multivariate logistic regression models. We found that XRCC1 Arg399Gln was significantly associated with an increased risk of breast cancer. Similarly, the XRCC1 Gln allele was significantly associated with an elevated risk in postmenopausal women and women with a high BMI (${\geq}24kg/m^2$). The OGG1 Cys allele provided a significant protective effect against developing cancer in women with a low BMI (< $24kg/m^2$). When analyzing the combined effects of these alleles on the risk of breast cancer, we found that individuals with ${\geq}2$ adverse genotypes (XRCC1 399Gln, APE1 148Asp, and OGG1 326Ser) were at a 2.18-fold increased risk of breast cancer (P = 0.027). In conclusion, our data indicate that Chinese women with the 399Gln allele of XRCC1 have an increased risk of breast cancer, and the combined effects of polymorphisms of BER genes may contribute to tumorigenesis.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권6호
• /
• pp.2935-2940
• /
• 2016

Breast cancer is the most frequent type of cancer diagnosed among women worldwide and also in Thailand. Estrogen and estrogen receptors exert important roles in its genesis and progression. Several cytokines have been reported to be involved in the microenvironment that promotes distant metastasis via modulation of immune and inflammatory responses to tumor cells. Estrogen receptor genetic polymorphisms and several cytokines have been reported to be associated with breast cancer susceptibility and aggressiveness. To investigate roles of genetic polymorphisms in estrogen receptor alpha (ESR1) and interleukin 6 (IL6), breast cancer patients and control subjects were recruited from the Division of Head, Neck and Breast Surgery (Siriraj Hospital, Bangkok, Thailand). Polymorphisms in ESR1 (rs3798577) and IL6 (rs1800795 and rs1800797) were evaluated by real-time PCR in 391 breast cancer patients and 79 healthy controls. Associations between genetic polymorphisms and clinicopathological data were determined. There was no association between genetic polymorphisms and breast cancer susceptibility. However the ESR1 rs3798577 CT genotype was associated with presence of lymphovascular invasion (OR=2.07, 95%CI 1.20-3.56, p=0.009) when compared to the TT genotype. IL6 rs1800795 CC genotype was associated with presence of extranodal extension (OR= 2.30, 95%CI 1.23-4.31, p=0.009) when compared to the GG genotype. Survival analysis showed that IL6 rs1800797 AG or AA genotypes were associated with lower disease-free survival. These findings indicate that polymorphisms in ESR1 and IL6 contribute to aggressiveness of breast cancer and may be used to identify high risk patients.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권9호
• /
• pp.4019-4023
• /
• 2015

Background: Breast cancer is the most frequently occurring cancer in women and the most common cause of cancer death worldwide. Materials and Methods: A cross-sectional study was carried out among 792 female undergraduate students in public universities in Klang Valley, Malaysia, from January to April 2011. Data were collected using a validated questionnaire developed for this study. Results: The mean age of respondents was $21.7{\pm}1.2$ years. Most of them were single (96.8%), Malay (91.9%) and 150 (19.6%) claimed they had practiced BSE. There was a significant differences between performers and non-performers correlated to age, marital status, check breast by doctor, and being trained about BSE. Performers had lower mean scores for perceived barriers and susceptibility and higher mean score for confidence. Stepwise logistic regression analysis yielded four significant predictor variables. Conclusions: Overall our findings indicate that the practice of BSE while perceived as being important is not frequently practiced among female in Malaysia. Targeted education should be implemented to improve early detection of breast cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권4호
• /
• pp.1599-1603
• /
• 2012

Objectives: Since methylenetetrahydrofolate reductase (MTHFR) maintains the balance of circulating folate and methionine and blocks the formation of homocysteine, its regulation in relation to different cancers has extensively been studied in different populations. However, information on Pakistani breast cancer patients is lacking. The MTHFR gene has two most common mutations that are single nucleotide additions which result in change of amino acids C677T to Ala222val and A1298C to Glu429Ala. Methodology: 110 sporadic breast patients with no prior family history of cancer or any other type of genetic disorders along with 110 normal individuals were screened for mutations in exons 1 to exon 9 using single strand conformational polymorphism, RFLP and sequencing analyzer. Results: The p values for the 677CC, 677CT, and 677TT genotypes were 0.223, 0.006, and 0.077, respectively. Those for the 1298AA, 1298AC, and 1298CC genotypes were 0.555, 0.009, and 0.003, respectively. Conclusions: We found an overall a significant, weak inverse association between breast cancer risk and the 677TT genotype and an inverse association with the 1298C variant. These results for MTHFR polymorphism might be population specific in sporadic breast cancer affected patients but many other factors need to be excluded before making final conclusions including folate intake, population and disease heterogeneity.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권sup3호
• /
• pp.23-26
• /
• 2016

Breast cancer (BC) is the most common cancer and the second cause of mortality in women all around the world. It is caused by several factors including genetic determinants, so that both genetic susceptibility factors and environmental factors are involved in the etiology. Significance of genes functioning in steroid hormone synthesis and metabolism are well established in breast cancer susceptibility. In this study, 134 women with BC and 135 normal controls were analyzed for their genotypes for the polymorphisms, rs743572, rs10046 and rs4646903, resided in CYP17, CYP19 and CYP1A1 genes, respectively. Significant differences in distributions of allele and genotype frequencies were found for the rs10046 polymorphism in CYP19 (p-value=0.01, OR (CI 95%) =1.59 (1.1-2.3), p-value=0.04, OR (CI 95%) =1.7 (1.1-2.5) respectively). For rs743,572 and rs 4646903 polymorphisms, no significant associations were observed. A significant association was observed between the rs10046 polymorphism of the CYP19gene and breast cancer in Iranian patients. Due to inconsistent previous results, more studies in different populations with larger sample sizes are indicated.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권11호
• /
• pp.7007-7010
• /
• 2013

Background: In the literature, data concerning the relationship between breast cancer and HLA class II gene polymorphisms are limited, so the aim of this study was to determine if HLA-DQB1 and HLA-DRB1 MHC class-II alleles may confer susceptibility or resistance to the disease among Jordanian females. Materials and Methods: This case control study enrolled 56 Royal Hospital breast cancer patients and 60 age matched healthy controls, all of whom provided blood samples (2011-2013). A questionnaire was filled after signing a consent form and DNA was extracted, nucleic acids being amplified for assessment of HLA-DQB1 and HLA-DRB1 alleles by muliplex INNO-LiPA and allele typing carried out by reverse hybridization. Comparison of HLA-DQB1 and HLA-DRB1 allele distributions was carried out with paired t-test and chi-square statistics. Risk factors were assessed by odd ratios with 95% confidence intervals. Results: A significant negative correlation was observed between $HLADQB1^*$ 02 alleles and breast cancers (p=0.013). No significant associations were observed among $HLADQB1^*$ 03, 04, 05 and 06 or among $HLA-DRB1^*$ 01, 03, 04, 07, 08, 10, 11, 13, 14 and 15. Conclusions: $HLADQB1^*$ 02 alleles may provide positive protection against breast tumor risk among Jordanians, but not $HLADQB1^*$ 03, 04, 05 and 06 or $HLA-DRB1^*$ 01, 03, 04, 07, 08, 10, 11, 13, 14 and 15 alleles.