Ji-Yeob Choi

BACKGROUND: Global DNA hypomethylation may result in chromosomal instability and oncogene activation, and as a surrogate of systemic methylation activity, may be associated with breast cancer risk. METHODS: Samples and data were obtained from women with incident early-stage breast cancer (I-IIIa) and women who were cancer free, frequency matched on age and race. In preliminary analyses, genomic methylation of leukocyte DNA was determined by measuring 5-methyldeoxycytosine (5-mdC), as well as met

Iron overload may increase prostate cancer risk through stimulation of oxidative stress, and endogenous pro- and antioxidant capabilities, i.e. manganese superoxide dismutase (MnSOD) and myeloperoxidase (MPO), may modify these associations. We investigated this hypothesis in the Carotene and Retinol Efficacy Trial cohort in a nested case-control study. Although there was no association between iron intake and risk overall, there was a suggestion of increased risk of clinically aggressive prostat

Oxidative stress, associated with aging and inflammation, is likely to play a role in the etiology of prostate cancer. We evaluated potential associations between gene variants that result in reduced neutralization of reactive oxygen species (ROS; MnSOD Ala-16Val, CAT -262 C>T, and GPX1 Pro200Leu) and prostate cancer risk among 724 men with incident prostate cancer who participated in the Carotene and Retinol Efficacy Trial (CARET) cohort, a randomized trial for the prevention of lung cancer amo

BACKGROUND: Older paternal age may increase the germ cell mutation rate in the offspring. Maternal age may also mediate in utero exposure to pregnancy hormones in the offspring. To evaluate the association between paternal and maternal age at birth with the risk of breast cancer in female offspring, a case-control study was conducted in Korea. METHODS: Histologically confirmed breast cancer cases (n = 1,011) and controls (n = 1,011) with no present or previous history of cancer, matched on year

This study therefore suggests that the CYP2E1 c2 allele may influence the individual susceptibility to breast cancer in alcohol-consuming women.

Our findings suggest that CYP2E1 and NQO1 genotypes may play an important role in development of smoking related bladder cancer among Korean men.

We examined whether common single nucleotide polymorphisms (SNP) in SULT1A1 (c.779G>A, *14A>G, and *85C>T) and SULT1E1 (IVS1-447C>A, IVS4-1653T>C, and *959G>A) genes influenced the risk and survival of breast cancer. Our study population consisted of 989 histologically confirmed sporadic breast cancer patients and 1,054 controls without history of cancer recruited from three teaching hospitals in Seoul. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by logistic regression

PURPOSE: Numerous chemotherapeutic agents are cytotoxic through generation of reactive species, and variability in genes related to oxidative stress may influence disease-free survival (DFS). We examined relationships between DFS and variants in NOS3, as well as NQO1, NQO2, and CBR3, among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial (S8897). EXPERIMENTAL DESIGN: In the parent trial, women were assigned according to prognostic features; the high-risk

Among patients receiving adjuvant therapy for breast cancer, there is variability in treatment outcomes, and it is unclear which patients will receive the most benefit from treatment and which will have better disease-free survival. To date, most studies of breast cancer prognosis have focused on tumor characteristics, but it is likely that pharmacogenetics, genetic variability in the metabolism of therapeutic agents, also plays a role in the prediction of survival. In this paper, we briefly dis

PURPOSE: It is inconclusive whether reproductive factors, which are known as risk factors of breast cancer, also influence survival. We investigated overall and subtype-specific associations between reproductive factors and breast cancer survival. METHODS: Among 3,430 incident breast cancer patients who enrolled in the Seoul Breast Cancer Study, 269 patients (7.8%) died and 528 patients (15.4%) recurred. The overall and subtype-specific associations of reproductive factors including age at menar

OBJECTIVE: To examine the associations between modifiable risk factors and glycemic status changes in individuals with prediabetes. RESEARCH DESIGN AND METHODS: A total of 10,358 individuals with prediabetes defined by their fasting blood glucose and HbA1c levels from the Health Examinees-Gem study were included in the present study. Modifiable factors, including BMI, abdominal obesity, smoking status, physical activity, alcohol consumption, diet quality, hypertension, and dyslipidemia, were exa

We investigated the role of common genetic variation in immune-related genes on breast cancer disease-free survival (DFS) in Korean women. 107 breast cancer patients of the Seoul Breast Cancer Study (SEBCS) were selected for this study. A total of 2,432 tag single nucleotide polymorphisms (SNPs) in 283 immune-related genes were genotyped with the GoldenGate Oligonucleotide pool assay (OPA). A multivariate Cox-proportional hazard model and polygenic risk score model were used to estimate the effe