Radioactive Iodine Therapy Did Not Significantly Increase the Incidence and Recurrence of Subsequent Breast Cancer.

CONTEXT: Previous studies on the extent to which radioactive iodine (RAI) therapy for thyroid cancer increases the risk of subsequently developing breast cancer have given conflicting results. OBJECTIVE: This study aimed to evaluate the effect of RAI treatment on breast cancer development and recurrence among female patients with primary thyroid cancer. DESIGN: This was a retrospective cohort study. The risk of subsequent breast cancer associated with RAI and its dose in hazard ratios (HRs) with 95% confidential intervals (CIs) were calculated using time-dependent Cox proportional hazard models. PATIENTS: A total of 6150 patients with thyroid cancer enrolled between 1973 and 2009 were followed until December 2012. Of these, 3631 (59.0%) received RAI therapy. During the follow-up period, 99 primary breast cancers were diagnosed. MAIN OUTCOME MEASURE: Risk of breast cancer development according to RAI therapy and RAI dose during treatment for primary thyroid cancer. RESULTS: RAI therapy did not significantly increase the incidence of subsequent breast cancer among female patients (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.22-1.06) when a 2-year latency period was accounted for. High-dose RAI (≥120 mCi) was associated with a reduced incidence of subsequent breast cancer (HR, 0.17; 95% CI, 0.05-0.62) in the cohort with a 2-year latency period. CONCLUSIONS: The long-term follow-up results of this study suggest that RAI treatment for patients with thyroid cancer may not increase the risk or recurrence of breast cancer.

Gene polymorphisms in the ornithine decarboxylase-polyamine pathway modify gastric cancer risk by interaction with isoflavone concentrations.

BACKGROUND: The study aimed to examine the association between genes encoding molecules in the ornithine decarboxylase (ODC)-polyamine pathway (ODC1, AMD1, NQO1, NOS2A, and OAZ2) and gastric cancer risk and whether the gene-phytoestrogen interaction modifies gastric cancer risk. METHODS: Among 76 gastric cancer cases and their 1:4 matched controls within the Korean Multi-center Cancer Cohort, a total of 30 SNPs in five genes involved in the ODC pathway were primarily analyzed. The second-stage genotyping in 388 matched case-control sets was conducted to reevaluate the significant SNPs interacting with phytoestrogens during the primary analysis. The summary odds ratios (ORs) [95 % confidence intervals (CIs)] for gastric cancer were estimated. Interaction effects between the SNPs and plasma concentrations of phytoestrogens (genistein, daidzein, equol, and enterolactone) were evaluated. RESULTS: In the pooled analysis, NQO1 rs1800566 showed significant genetic effects on gastric cancer without heterogeneity [OR 0.83 (95 % CI 0.70-0.995)] and a greater decreased risk at high genistein/daidzein levels [OR 0.36 (95 % CI 0.15-0.90) and OR 0.26 (95 % CI 0.10-0.64), respectively; p interaction < 0.05]. Risk alleles of AMD1 rs1279599, AMD1 rs7768897, and OAZ2 rs7403751 had a significant gene-phytoestrogen (genistein and daidzein) interaction effect to modify the development of gastric cancer. They had an increased gastric cancer risk at low isoflavone levels, but a decreased risk at high isoflavone levels (p interaction < 0.01). CONCLUSIONS: Our findings suggest that common variants in the genes involved in the ODC pathway may contribute to the risk of gastric cancer possibly by modulating ODC polyamine biosynthesis or by interaction between isoflavones and NQO1, OAZ2, and AMD1.

Interaction effects between genes involved in the AKT signaling pathway and phytoestrogens in gastric carcinogenesis: a nested case-control study from the Korean Multi-Center Cancer Cohort.

SCOPE: To investigate whether genes involved in AKT/nuclear factor kappa B signaling and/or gene-environment interactions between the genes and phytoestrogens may be susceptible factors for gastric cancer. METHODS AND RESULTS: The representative single nucleotide polymorphisms (SNPs) identified during the primary analysis (screening a total of 622 SNPs within ± 5 kbp of the 51 target gene locations) were further investigated in 317 matched case-control sets. The summary odds ratios (ORs) and 95% confidence intervals (CIs) for gastric cancer were calculated. Interaction effects between the SNPs and phytoestrogen biomarkers (genistein, daidzein, equol, and enterolactone) were computed. CDK1 rs4145643, FAS rs6586161, and FAS rs1468063 in the AKT signaling pathway presented significant genetic effects on gastric cancer (OR = 0.81 (95% CI: 0.66-0.99) for CDK1 rs4145643; OR = 1.27 (95% CI: 1.03-1.58) for FAS rs6586161; OR = 1.29 (95% CI: 1.03-1.56) for FAS rs1468063; Cochran Q statistics > 0.10). Risk alleles of FAS rs6586161, FAS rs1468063, MAP3K1 rs16886448, and MAP3K1 rs252902 showed significant interaction effects with enterolactone (p(interaction) < 0.05). CONCLUSION: CDK1 and FAS genes involved in AKT signaling and influenced by anti-carcinogenic property of phytoestrogens can play a role as susceptible genetic factors in gastric carcinogenesis. FAS and MAP3K1 genes significantly interact with enterolactone, thereby modifying the individual's risk for gastric cancer.

Genetic susceptibility on CagA-interacting molecules and gene-environment interaction with phytoestrogens: a putative risk factor for gastric cancer.

OBJECTIVES: To evaluate whether genes that encode CagA-interacting molecules (SRC, PTPN11, CRK, CRKL, CSK, c-MET and GRB2) are associated with gastric cancer risk and whether an interaction between these genes and phytoestrogens modify gastric cancer risk. METHODS: In the discovery phase, 137 candidate SNPs in seven genes were analyzed in 76 incident gastric cancer cases and 322 matched controls from the Korean Multi-Center Cancer Cohort. Five significant SNPs in three genes (SRC, c-MET and CRK) were re-evaluated in 386 cases and 348 controls in the extension phase. Odds ratios (ORs) for gastric cancer risk were estimated adjusted for age, smoking, H. pylori seropositivity and CagA strain positivity. Summarized ORs in the total study population (462 cases and 670 controls) were presented using pooled- and meta-analysis. Plasma concentrations of phytoestrogens (genistein, daidzein, equol and enterolactone) were measured using the time-resolved fluoroimmunoassay. RESULTS: SRC rs6122566, rs6124914, c-MET rs41739, and CRK rs7208768 showed significant genetic effects for gastric cancer in both the pooled and meta-analysis without heterogeneity (pooled OR = 3.96 [95% CI 2.05-7.65], 1.24 [95% CI = 1.01-1.53], 1.19 [95% CI = 1.01-1.41], and 1.37 [95% CI = 1.15-1.62], respectively; meta OR = 4.59 [95% CI 2.74-7.70], 1.36 [95% CI = 1.09-1.70], 1.20 [95% CI = 1.00-1.44], and 1.32 [95% CI = 1.10-1.57], respectively). Risk allele of CRK rs7208768 had a significantly increased risk for gastric cancer at low phytoestrogen levels (p interaction<0.05). CONCLUSIONS: Our findings suggest that SRC, c-MET and CRK play a key role in gastric carcinogenesis by modulating CagA signal transductions and interaction between CRK gene and phytoestrogens modify gastric cancer risk.