Are you Sabapathy Balasubramanian?

Claim your profile

Publications (7)57.08 Total impact

  • Source
    Article: Evidence of Gene–Environment Interactions between Common Breast Cancer Susceptibility Loci and Established Environmental Risk Factors
    [show abstract] [hide abstract]
    ABSTRACT: Author Summary Breast cancer involves combined effects of numerous genetic, environmental, and behavioral risk factors that are unique to each individual. High risk genes, such as BRCA1 and BRCA2 , account for only a small proportion of disease occurrence. Recent genome-wide research has identified more than 20 common genetic variants, which individually alter breast cancer risk very moderately. We undertook an international collaborative study to determine whether the effect of these genetic variants vary with environmental factors, such as parity, body mass index (BMI), height, oral contraceptive use, menopausal hormone therapy use, alcohol consumption, cigarette smoking, and physical activity, which are known to affect risk of developing breast cancer. Using pooled data from 24 studies of the Breast Cancer Association Consortium (BCAC), we provide first convincing evidence that the breast cancer risk associated with a genetic variant in LSP1<
    PLoS Genet. 03/2013; 9(3):e1003284.
  • Source
    Article: Evidence of Gene-Environment Interactions between Common Breast Cancer Susceptibility Loci and Established Environmental Risk Factors.
    [show abstract] [hide abstract]
    ABSTRACT: Various common genetic susceptibility loci have been identified for breast cancer; however, it is unclear how they combine with lifestyle/environmental risk factors to influence risk. We undertook an international collaborative study to assess gene-environment interaction for risk of breast cancer. Data from 24 studies of the Breast Cancer Association Consortium were pooled. Using up to 34,793 invasive breast cancers and 41,099 controls, we examined whether the relative risks associated with 23 single nucleotide polymorphisms were modified by 10 established environmental risk factors (age at menarche, parity, breastfeeding, body mass index, height, oral contraceptive use, menopausal hormone therapy use, alcohol consumption, cigarette smoking, physical activity) in women of European ancestry. We used logistic regression models stratified by study and adjusted for age and performed likelihood ratio tests to assess gene-environment interactions. All statistical tests were two-sided. We replicated previously reported potential interactions between LSP1-rs3817198 and parity (Pinteraction = 2.4×10(-6)) and between CASP8-rs17468277 and alcohol consumption (Pinteraction = 3.1×10(-4)). Overall, the per-allele odds ratio (95% confidence interval) for LSP1-rs3817198 was 1.08 (1.01-1.16) in nulliparous women and ranged from 1.03 (0.96-1.10) in parous women with one birth to 1.26 (1.16-1.37) in women with at least four births. For CASP8-rs17468277, the per-allele OR was 0.91 (0.85-0.98) in those with an alcohol intake of <20 g/day and 1.45 (1.14-1.85) in those who drank ≥20 g/day. Additionally, interaction was found between 1p11.2-rs11249433 and ever being parous (Pinteraction = 5.3×10(-5)), with a per-allele OR of 1.14 (1.11-1.17) in parous women and 0.98 (0.92-1.05) in nulliparous women. These data provide first strong evidence that the risk of breast cancer associated with some common genetic variants may vary with environmental risk factors.
    PLoS Genetics 03/2013; 9(3):e1003284. · 8.69 Impact Factor
  • Article: Osteoprotegerin (OPG) and related proteins (RANK, RANKL and TRAIL) in thyroid disease.
    Sumit K Sood, Sabapathy Balasubramanian, Sue Higham, Malee Fernando, Barney Harrison
    [show abstract] [hide abstract]
    ABSTRACT: Osteoprotegerin (OPG), receptor activator of nuclear factor kappaB (RANK), RANK ligand (RANKL), and TNF related apoptosis inducing ligand (TRAIL) are the key proteins in the development of bone metastases. Osteoprotegerin improves tumor cell survival and inhibits TRAIL induced apoptosis of cancer cell lines. It also binds to RANKL and inhibits its interaction with RANK (cell surface receptor), which influences osteoclast formation and function. The aim of the present study was to characterize the expression of OPG, RANK, RANKL, and TRAIL in benign and malignant thyroid tissue and thyroid cell lines. Archived thyroid tissue from 79 patients (60 differentiated thyroid cancers and 19 benign thyroids) was stained for OPG, RANK, RANKL, and TRAIL by immunohistochemistry. Staining was assessed semiquantitatively and correlated with pathology. Western blots were performed on three human thyroid cell lines: Nthy-ori 3-1 (thyroid follicular epithelium), FTC-133 (follicular thyroid carcinoma), and K1E7 (subclone of papillary thyroid carcinoma). Osteoprotegerin and RANKL staining was cytoplasmic; RANK staining was nuclear; and TRAIL staining was predominantly cytoplasmic. All four proteins were expressed in benign and malignant tissue. There was significant difference in RANK expression between malignant and benign tissue (8 vs. 84%, respectively; Fisher's exact test; P < 0.001). RANKL expression was significantly increased in malignant tissue (Fisher's exact test; P = 0.04). Western blotting showed OPG expression in all cell lines and TRAIL in none. RANK and RANKL were not detected in papillary and follicular cell lines, respectively. Nuclear expression of RANK protein in thyroid tissue is paradoxical; it could be due to nuclear migration after ligand binding. Suppression of RANK and increased expression of RANKL in malignant tissue warrant further investigation.
    World Journal of Surgery 09/2011; 35(9):1984-92. · 2.36 Impact Factor
  • Article: A role for XRCC2 gene polymorphisms in breast cancer risk and survival.
    [show abstract] [hide abstract]
    ABSTRACT: The XRCC2 gene is a key mediator in the homologous recombination repair of DNA double strand breaks. It is hypothesised that inherited variants in the XRCC2 gene might also affect susceptibility to, and survival from, breast cancer. The study genotyped 12 XRCC2 tagging single nucleotide polymorphisms (SNPs) in 1131 breast cancer cases and 1148 controls from the Sheffield Breast Cancer Study (SBCS), and examined their associations with breast cancer risk and survival by estimating ORs and HRs, and their corresponding 95% CIs. Positive findings were further investigated in 860 cases and 869 controls from the Utah Breast Cancer Study (UBCS) and jointly analysed together with available published data for breast cancer risk. The survival findings were further confirmed in studies (8074 cases) from the Breast Cancer Association Consortium (BCAC). The most significant association with breast cancer risk in the SBCS dataset was the XRCC2 rs3218408 SNP (recessive model p=2.3×10(-4), minor allele frequency (MAF)=0.23). This SNP yielded an OR(rec) of 1.64 (95% CI 1.25 to 2.16) in a two-site analysis of SBCS and UBCS, and a meta-OR(rec) of 1.33 (95% CI 1.12 to 1.57) when all published data were included. This SNP may mark a rare risk haplotype carried by two in 1000 of the control population. Furthermore, the XRCC2 coding R188H SNP (rs3218536, MAF=0.08) was significantly associated with poor survival, with an increased per-allele HR of 1.58 (95% CI 1.01 to 2.49) in a multivariate analysis. This effect was still evident in a pooled meta-analysis of 8781 breast cancer patients from the BCAC (HR 1.19, 95% CI 1.05 to 1.36; p=0.01). These findings suggest that XRCC2 SNPs may influence breast cancer risk and survival.
    Journal of Medical Genetics 07/2011; 48(7):477-84. · 6.36 Impact Factor
  • Article: Five polymorphisms and breast cancer risk: results from the Breast Cancer Association Consortium.
    [show abstract] [hide abstract]
    ABSTRACT: Previous studies have suggested that minor alleles for ERCC4 rs744154, TNF rs361525, CASP10 rs13010627, PGR rs1042838, and BID rs8190315 may influence breast cancer risk, but the evidence is inconclusive due to their small sample size. These polymorphisms were genotyped in more than 30,000 breast cancer cases and 30,000 controls, primarily of European descent, from 30 studies in the Breast Cancer Association Consortium. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) as a measure of association. We found that the minor alleles for these polymorphisms were not related to invasive breast cancer risk overall in women of European descent: ECCR4 per-allele OR (95% CI) = 0.99 (0.97-1.02), minor allele frequency = 27.5%; TNF 1.00 (0.95-1.06), 5.0%; CASP10 1.02 (0.98-1.07), 6.5%; PGR 1.02 (0.99-1.06), 15.3%; and BID 0.98 (0.86-1.12), 1.7%. However, we observed significant between-study heterogeneity for associations with risk for single-nucleotide polymorphisms (SNP) in CASP10, PGR, and BID. Estimates were imprecise for women of Asian and African descent due to small numbers and lower minor allele frequencies (with the exception of BID SNP). The ORs for each copy of the minor allele were not significantly different by estrogen or progesterone receptor status, nor were any significant interactions found between the polymorphisms and age or family history of breast cancer. In conclusion, our data provide persuasive evidence against an overall association between invasive breast cancer risk and ERCC4 rs744154, TNF rs361525, CASP10 rs13010627, PGR rs1042838, and BID rs8190315 genotypes among women of European descent.
    Cancer Epidemiology Biomarkers &amp Prevention 06/2009; 18(5):1610-6. · 4.12 Impact Factor
  • Article: A common coding variant in CASP8 is associated with breast cancer risk.
    [show abstract] [hide abstract]
    ABSTRACT: The Breast Cancer Association Consortium (BCAC) has been established to conduct combined case-control analyses with augmented statistical power to try to confirm putative genetic associations with breast cancer. We genotyped nine SNPs for which there was some prior evidence of an association with breast cancer: CASP8 D302H (rs1045485), IGFBP3 -202 C --> A (rs2854744), SOD2 V16A (rs1799725), TGFB1 L10P (rs1982073), ATM S49C (rs1800054), ADH1B 3' UTR A --> G (rs1042026), CDKN1A S31R (rs1801270), ICAM5 V301I (rs1056538) and NUMA1 A794G (rs3750913). We included data from 9-15 studies, comprising 11,391-18,290 cases and 14,753-22,670 controls. We found evidence of an association with breast cancer for CASP8 D302H (with odds ratios (OR) of 0.89 (95% confidence interval (c.i.): 0.85-0.94) and 0.74 (95% c.i.: 0.62-0.87) for heterozygotes and rare homozygotes, respectively, compared with common homozygotes; P(trend) = 1.1 x 10(-7)) and weaker evidence for TGFB1 L10P (OR = 1.07 (95% c.i.: 1.02-1.13) and 1.16 (95% c.i.: 1.08-1.25), respectively; P(trend) = 2.8 x 10(-5)). These results demonstrate that common breast cancer susceptibility alleles with small effects on risk can be identified, given sufficiently powerful studies.
    Nature Genetics 04/2007; 39(3):352-8. · 35.53 Impact Factor
  • Article: Endostatin gene variation and protein levels in breast cancer susceptibility and severity
    [show abstract] [hide abstract]
    ABSTRACT: Abstract Background Endostatin is a potent endogenous anti-angiogenic agent which inhibits tumour growth. A non-synonymous coding polymorphism in the Endostatin gene is thought to affect Endostatin activity. We aimed to determine the role of this Endostatin polymorphism in breast cancer pathogenesis and any influence on serum Endostatin levels in healthy volunteers. Endostatin protein expression on a breast cancer micro array was also studied to determine any relationship to genotype and to breast cancer prognosis. Methods The 4349G > A (coding non-synonymous) polymorphism in exon 42 of the Endostatin gene was genotyped in approximately 846 breast cancer cases and 707 appropriate controls. In a separate healthy cohort of 57 individuals, in addition to genotyping, serum Endostatin levels were measured using enzyme linked immunosorbant assay (ELISA). A semi-quantitative assessment of Endostatin protein expression on immunostained tissue micro arrays (TMA) constructed from breast cancer samples of patients with genotype data was performed. Results The rare allele (A) was significantly associated with invasive breast cancers compared to non-invasive tumours (p = 0.03), but there was no association with tumour grade, nodal status, vascular invasion or overall survival. There was no association with breast cancer susceptibility. Serum Endostatin levels and Endostatin protein expression on the tissue micro array were not associated with genotype. Conclusion The Endostatin 4349A allele is associated with invasive breast cancer. The Endostatin 4349G > A polymorphism however does not appear to be associated with breast cancer susceptibility or severity in invasive disease. By studying circulating levels and tumour Endostatin protein expression, we have shown that any influence of this polymorphism is unlikely to be through an effect on the levels of protein produced.
    BMC Cancer. 01/2007;