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1.  Factors associated with serum thyroglobulin levels in a population living in Belarus 
Clinical endocrinology  2013;79(1):10.1111/cen.12107.
Serum thyroglobulin (Tg) has been associated with a number of thyroid disorders and has been proposed as an indicator of iodine deficiency in a population. However, few studies have addressed the epidemiology of Tg in a population-based setting or in the context of exposure to radioactive iodine-131 (I-131). Our objective was to evaluate baseline levels of Tg in relation to socio-demographic characteristics, iodine status, and thyroid function for individuals exposed to I-131.
A population-based cohort assembled in Belarus following the Chornobyl accident provided demographic factors, clinical data, and physiological measurements.
Our analytic sample included 10,344 subjects of whom 7,890 had no thyroid disease and 2,454 had evidence of structural or functional thyroid abnormality.
Standardized assays were used to measure serum Tg, urinary iodine, TSH, and antibodies to Tg and thyroid peroxidase. Ultrasound was used to assess the presence of nodules and estimate thyroid volume.
In the fully adjusted model, percent change in Tg was significantly increased among females, smokers, and subjects of older age and Tg increased with decreasing urinary iodine concentration, increasing serum TSH and increasing thyroid volume (p-values for trend < 0.0001), and presence of thyroid nodules (p < 0.05). We found a complex interaction between region of residence, rural/urban living, presence/absence of thyroid abnormalities, and serum Tg (p < 0.0001).
In residents of Belarus, serum Tg is significantly related to presence of thyroid abnormalities as well as indicators of thyroid function and iodine deficiency and, therefore, could be used to characterize the iodine status and thyroid function of individuals in the context of epidemiological study.
PMCID: PMC3870891  PMID: 23190420
Thyroglobulin; Iodine; Thyroid; Chernobyl Nuclear Accident; Republic of Belarus
2.  Plasma cell neoplasms in U.S. solid organ transplant recipients 
Transplant recipients have elevated risk for plasma cell neoplasms (PCNs, comprising multiple myeloma and plasmacytoma), but little is known about risk factors in the transplant setting. Through linkage of the U.S. solid organ transplant registry with 15 state/regional cancer registries, we identified 140 PCNs in 202,600 recipients (1987–2009). PCN risk was 1.8-fold increased relative to the general population (standardized incidence ratio [SIR] 1.80, 95%CI 1.51–2.12). Among cases, 102 were multiple myeloma (SIR 1.41) and 38 were plasmacytoma (SIR 7.06). PCN incidence increased with age, but due to the rarity of PCNs in younger people in the general population, SIRs were highest in younger transplant recipients (p=0.03). PCN risk was especially high in recipients who were Epstein-Barr virus (EBV) seronegative at transplantation (SIR 3.93). EBV status was known for 18 tumors, of which 7 (39%) were EBV positive. Following liver transplantation, PCN risk was higher in recipients with cholestatic liver disease (SIR 2.78); 5 of these cases had primary biliary cirrhosis (PBC). A role for primary EBV infection after transplantation is supported by the increased PCN risk in young EBV seronegative recipients and the presence of EBV in tumors. PBC may be another risk factor, perhaps by causing chronic immune activation.
PMCID: PMC3676887  PMID: 23635036
multiple myeloma; plasmacytoma; post-transplant lymphoproliferative disorder; Epstein-Barr virus; immunosuppression; primary biliary cirrhosis
3.  Obesity-related hormones and endometrial cancer among postmenopausal women: a nested case–control study within the B~FIT cohort 
Endocrine-related cancer  2013;20(1):151-160.
Endometrial cancer risk is strongly influenced by obesity, but the mechanisms of action remain unclear. Leptin and adiponectin, secreted from adipose tissue, reportedly play a role in such carcinogenic processes as cell proliferation, angiogenesis, and insulin regulation. In this case–control study, nested within the Breast and Bone Follow-up of the Fracture Intervention Trial (n = 15 595), we assessed pre-diagnostic serum leptin, total adiponectin, and high-molecular-weight (HMW) adiponectin in relation to endometrial cancer among postmenopausal women. During the 10-year follow-up, 62 incident endometrial cases were identified and matched to 124 controls on age, geographical site, time of fasting blood draw at baseline (1992–1993), and trial participation status. Adipokines and C-peptide were measured by ELISA. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated via conditional logistic regression, with exposures categorized in tertiles (T). Multivariable models considered C-peptide, BMI (kg/m2), and estradiol (E2) as potential confounders. Endometrial cancer risk was significantly associated with higher leptin levels, adjusted for E2 and C-peptide (ORT3 vs T1 = 2.96; 95% CI, 1.21–7.25; P trend <0.01). After further adjustment for BMI, the estimates were attenuated and the positive trend was no longer statistically significant (ORT3 vs T1 = 2.11; 95% CI, 0.69–6.44; P trend = 0.18). No significant associations were observed with adiponectin or HMW adiponectin and endometrial cancer. Our findings with leptin suggest that the leptin–BMI axis might increase endometrial cancer risk through mechanisms other than estrogen-driven proliferation. Continued exploration of these pathways in larger prospective studies may help elucidate mechanisms underlying observed obesity–endometrial cancer associations.
PMCID: PMC4038326  PMID: 23222000
endometrial cancer; adiponectin; leptin; obesity
4.  Population-based absolute risk estimation with survey data 
Lifetime data analysis  2013;20(2):252-275.
Absolute risk is the probability that a cause-specific event occurs in a given time interval in the presence of competing events. We present methods to estimate population-based absolute risk from a complex survey cohort that can accommodate multiple exposure-specific competing risks. The hazard function for each event type consists of an individualized relative risk multiplied by a baseline hazard function, which is modeled nonparametrically or parametrically with a piecewise exponential model. An influence method is used to derive a Taylor-linearized variance estimate for the absolute risk estimates. We introduce novel measures of the cause-specific influences that can guide modeling choices for the competing event components of the model. To illustrate our methodology, we build and validate cause-specific absolute risk models for cardiovascular and cancer deaths using data from the National Health and Nutrition Examination Survey. Our applications demonstrate the usefulness of survey-based risk prediction models for predicting health outcomes and quantifying the potential impact of disease prevention programs at the population level.
PMCID: PMC3883938  PMID: 23686614
Absolute risk; Censored data; Crude risk; Cumulative incidence; NHANES; Survey cohort
Cancer causes & control : CCC  2013;24(4):749-757.
Emerging data suggest that ovarian cancers differ by tumor grade. However, the reliability of microscopic grade as assigned in the general medical community and reflected in cancer registries is unknown.
We examined grade agreement between two gynecologic pathologists and the Surveillance Epidemiology and End Results (SEER) program. Grade agreement was assessed with percent observer agreement and kappa coefficients for 664 invasive ovarian carcinomas from SEER’s Residual Tissue Repository. We used three-tier and two-tier grading schemes. A random subset of ovarian carcinomas was selected to compare intra- and inter-pathologist agreement.
Five hundred and eighty-six of SEER’s 664 tumors were confirmed invasive. Percent agreement was 49% with fair kappa coefficient = 0.25 (95% CI: 0.20 to 0.30) for the 664 tumors. Agreement improved slightly when restricted to the 586 confirmed invasive cancers; was better for high than low grade tumors, two-tier than three-tier grading systems, and within (66%) than between study pathologists (43%). Tumor grade was not a robust independent predictor of ovarian cancer-specific survival.
Grade agreement was fair irrespective of grading system between SEER and study pathologists. Recorded grade in SEER should be used with caution and is probably not a reliable metric for ovarian cancer epidemiology.
PMCID: PMC4000689  PMID: 23378140
epidemiology; ovarian cancer; tumor grade; SEER; kappa coefficient
6.  Global Changes in Gene Expression of Barrett's Esophagus Compared to Normal Squamous Esophagus and Gastric Cardia Tissues 
PLoS ONE  2014;9(4):e93219.
Barrett's esophagus (BE) is a metaplastic precursor lesion of esophageal adenocarcinoma (EA), the most rapidly increasing cancer in western societies. While the prevalence of BE is increasing, the vast majority of EA occurs in patients with undiagnosed BE. Thus, we sought to identify genes that are altered in BE compared to the normal mucosa of the esophagus, and which may be potential biomarkers for the development or diagnosis of BE.
We performed gene expression analysis using HG-U133A Affymetrix chips on fresh frozen tissue samples of Barrett's metaplasia and matched normal mucosa from squamous esophagus (NE) and gastric cardia (NC) in 40 BE patients.
Using a cut off of 2-fold and P<1.12E-06 (0.05 with Bonferroni correction), we identified 1324 differentially-expressed genes comparing BE vs NE and 649 differentially-expressed genes comparing BE vs NC. Except for individual genes such as the SOXs and PROM1 that were dysregulated only in BE vs NE, we found a subset of genes (n = 205) whose expression was significantly altered in both BE vs NE and BE vs NC. These genes were overrepresented in different pathways, including TGF-β and Notch.
Our findings provide additional data on the global transcriptome in BE tissues compared to matched NE and NC tissues which should promote further understanding of the functions and regulatory mechanisms of genes involved in BE development, as well as insight into novel genes that may be useful as potential biomarkers for the diagnosis of BE in the future.
PMCID: PMC3979678  PMID: 24714516
7.  Extensions of criteria for evaluating risk prediction models for public health applications 
Biostatistics (Oxford, England)  2012;14(2):366-381.
We recently proposed two novel criteria to assess the usefulness of risk prediction models for public health applications. The proportion of cases followed, PCF(p), is the proportion of individuals who will develop disease who are included in the proportion p of individuals in the population at highest risk. The proportion needed to follow-up, PNF(q), is the proportion of the general population at highest risk that one needs to follow in order that a proportion q of those destined to become cases will be followed (Pfeiffer, R.M. and Gail, M.H., 2011. Two criteria for evaluating risk prediction models. Biometrics 67, 1057–1065). Here, we extend these criteria in two ways. First, we introduce two new criteria by integrating PCF and PNF over a range of values of q or p to obtain iPCF, the integrated PCF, and iPNF, the integrated PNF. A key assumption in the previous work was that the risk model is well calibrated. This assumption also underlies novel estimates of iPCF and iPNF based on observed risks in a population alone. The second extension is to propose and study estimates of PCF, PNF, iPCF, and iPNF that are consistent even if the risk models are not well calibrated. These new estimates are obtained from case–control data when the outcome prevalence in the population is known, and from cohort data, with baseline covariates and observed health outcomes. We study the efficiency of the various estimates and propose and compare tests for comparing two risk models, both of which were evaluated in the same validation data.
PMCID: PMC3695651  PMID: 23087412
Area under the receiver operator characteristics curve (ROC); AUC; Discrimination; Discriminatory accuracy; Risk models; Study design
8.  An Aggregated Analysis of Hormonal Factors and Endometrial Cancer Risk by Parity 
Cancer  2012;119(7):1393-1401.
Nulliparity is associated with an increased risk of endometrial cancer. Less clear is whether nulliparity modifies the association between other established hormone-related risk factors. The proportion of nulliparous women has increased since the mid-1970s, but most individual studies are too small to test the hypothesis that endometrial cancer risk factors may be more strongly associated with risk among nulliparous women compared with parous women.
We aggregated data on 26,936 postmenopausal, Caucasian nulliparous women (360 endometrial cancers) and 146,583 postmenopausal Caucasian parous women (1,378 endometrial cancers) from four U.S. prospective studies (1979–2006). We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) in stratified analyses.
As expected, endometrial cancer risk was higher among nulliparous women than among parous women (HR, nulliparous vs. parous = 1.42, 95% CI 1.26 to 1.60). Stratified associations between endometrial cancer and hormone-related risk factors did not differ among nulliparous vs. parous women: among both groups, oral contraceptives and earlier menopause were associated with reduced risk. The highest HRs were for obesity; body mass index ≥30 kg/m2 (vs. <25 kg/m2) increased endometrial cancer risk three-fold among nulliparous (HR= 3.04, 95% CI 2.34 to 3.94) and parous (HR= 2.88, 95% CI 2.52 to 3.29) women.
The results from this large, pooled analysis of data from four large prospective studies suggest that nulliparity does not modify endometrial cancer risks associated with established hormone-related risk factors.
PMCID: PMC3744666  PMID: 23280123
endometrial cancer; nulliparity; reproductive history; oral contraceptives; hormonal; obesity
9.  Cytokine signaling pathway polymorphisms and AIDS-related non-Hodgkin lymphoma risk in the Multicenter AIDS Cohort Study 
AIDS (London, England)  2010;24(7):1025-1033.
Cytokine stimulation of B-cell proliferation may be an important etiologic mechanism for acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin lymphoma (NHL). The Epstein-Barr virus may be a co-factor, particularly for primary central nervous system (CNS) tumors, which are uniformly EBV-positive in the setting of AIDS. Thus, we examined associations of genetic variation in IL10 and related cytokine signaling molecules (IL10RA, CXCL12, IL13, IL4, IL4R, CCL5 and BCL6) with AIDS-related NHL risk and evaluated differences between primary CNS and systemic tumors. We compared 160 Multicenter AIDS Cohort Study (MACS) participants with incident lymphomas, of which 90 followed another AIDS diagnosis, to HIV-1-seropositive controls matched on duration of lymphoma-free survival post-HIV-1 infection (N=160) or post-AIDS diagnosis (N=90). We fit conditional logistic regression models to estimate odds ratios (ORs) and 95 percent confidence intervals (95%CIs). Carriage of at least one copy of the T allele for the IL10 rs1800871 (as compared to no copies) was associated with decreased AIDS-NHL risk specific to lymphomas arising from the CNS (CC vs. CT/TT: OR=0.3; 95%CI: 0.1, 0.7) but not systemically (CC vs. CT/TT: OR=1.0; 95%CI: 0.5, 1.9) (Pheterogeneity=0.03). Carriage of two copies of the “low IL10” haplotype rs1800896_A/rs1800871_T/rs1800872_A was associated with decreased lymphoma risk that varied by number of copies (Ptrend=0.02). None of the ORs for the other studied polymorphisms was significantly different from 1.0. Excessive IL10 response to HIV-1 infection may be associated with increased risk of NHL, particularly in the CNS. IL10 dysregulation may be an important etiologic pathway for EBV-related lymphomagenesis.
PMCID: PMC3950937  PMID: 20299965
cytokine; SNPs; AIDS-related lymphoma
10.  Prediagnosis Body Mass Index, Physical Activity, and Mortality in Endometrial Cancer Patients 
Higher body mass index (BMI) and inactivity have been associated with a higher risk of developing endometrial cancer, but the impact on endometrial cancer survival is unclear.
Among incident endometrial cancer case subjects in the National Institutes of Health–AARP Diet and Health Study, we examined associations of prediagnosis BMI (n = 1400) and physical activity (n = 875) with overall and disease-specific 5- and 10-year mortality. Using Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for tumor characteristics, treatment, and other risk factors. All statistical tests were two-sided.
Compared with women with a BMI in the range of 18.5 to less than 25kg/m2, the hazard ratios for 5-year all-cause mortality were 1.74 (95% CI = 1.13 to 2.66) for BMI in the range of 25 to less than 30kg/m2, 1.84 (95% CI = 1.17 to 2.88) for BMI in the range of 30 to less than 35kg/m2, and 2.35 (95% CI = 1.48 to 3.73) for BMI greater than or equal to 35kg/m2 (P trend < .001). Higher BMI was also statistically significantly associated with poorer endometrial cancer–specific but not cardiovascular disease 5-year mortality. Hazard ratio estimates for 10-year all-cause and endometrial cancer–specific mortality as related to BMI were similar to 5-year hazard ratio estimates, whereas 10-year cardiovascular disease mortality became statistically significant (HR = 4.08; 95% CI = 1.56 to 10.71 comparing extreme BMI groups). More physical activity was related to lower all-cause 5-year mortality (HR = 0.57, 95% CI = 0.33 to 0.98 for >7 hours/week vs never/rarely), but the association was attenuated after adjustment for BMI (HR = 0.64, 95% CI = 0.37 to 1.12). No association was observed between physical activity and disease-specific mortality.
Our findings suggest that higher prediagnosis BMI increases risk of overall and disease-specific mortality among women diagnosed with endometrial cancer, whereas physical activity lowers risk. Intervention studies of the effect of these modifiable lifestyle factors on mortality are needed.
PMCID: PMC3589256  PMID: 23297041
11.  Characterization of ELISA Detection of Broad-spectrum Anti- Epstein-Barr Virus Antibodies Associated with Nasopharyngeal Carcinoma 
Journal of medical virology  2012;85(3):524-529.
Epstein-Barr virus (EBV) infection is associated with undifferentiated nasopharyngeal carcinomas (NPC). A distinct seroreactivity pattern to EBV is predictive of subsequent risk of sporadic and familial nasopharyngeal carcinomas. There are currently no accepted screening tools for guiding the clinical management of individuals at high-risk for nasopharyngeal carcinomas, particularly unaffected relatives from nasopharyngeal carcinoma multiplex families. Therefore, the reproducibility of a panel of largely synthetic peptide-based anti-EBV antibody ELISAs was evaluated and their ability to distinguish nasopharyngeal carcinoma cases from controls was explored. IgG and IgA antibodies against 6 different EBV antigens (10 assays, total) were tested on sera from 97 individuals representing the full spectrum of anti-EBV seroprevalence (i.e., healthy individuals with no known EBV seroreactivity, healthy individuals with known EBV seroreactivity, and nasopharyngeal carcinoma cases). Each specimen was tested in triplicate to assess within-batch and across-batch variation, and the triplicate testing was repeated on two separate days. Reproducibility was assessed by the coefficients of variation (CV) and intraclass correlation coefficients (ICC). All markers were detectable in 17% or more of samples. For all but one marker, the overall, within-batch, and across-batch CVs were below 15%, and the ICCs were above 70% for all but three markers. Sensitivity of these markers to detect prevalent nasopharyngeal carcinomas ranged from 22–100%, and among unaffected controls, most distinguished those with and without known seropositivity. In conclusion, a large number of EBV markers can be measured reliably in serum samples using peptide-based anti-EBV ELISAs.
PMCID: PMC3553325  PMID: 23280934
Epstein-Barr virus; EBNA1; VCA; IgA; nasopharyngeal carcinoma; screening
12.  Declining Second Primary Ovarian Cancer After First Primary Breast Cancer 
Journal of Clinical Oncology  2013;31(6):738-743.
Although ovarian cancer incidence rates have declined in the United States, less is known of ovarian cancer trends among survivors of breast cancer. Therefore, we examined second primary ovarian cancers after first primary breast cancer.
Data were obtained from the Surveillance, Epidemiology, and End Results program (1973 to 2008). Standardized incidence ratios (SIRs) were calculated as the observed numbers of ovarian cancers among survivors of breast cancer compared with the expected numbers in the general population. Absolute rates were measured as the incidence rates for second primary ovarian cancer by year of diagnosis of the first primary breast cancer adjusted for age of breast cancer diagnosis and years since diagnosis.
SIRs for second primary ovarian cancer were elevated over the entire study period (SIR, 1.24; 95% CI, 1.2 to 1.3), whereas the absolute rates declined with an estimated annual percentage change near 1% (−1.34% to −0.09% per year). Secular trends for second ovarian cancers were similar after estrogen receptor (ER) –positive and ER-negative breast cancers, whereas the age-specific patterns varied significantly by ER expression (P for interaction < .001). The largest SIR was among women age less than 50 years with ER-negative breast cancer (SIR, 4.35; 95% CI, 3.5 to 5.4).
Persistently elevated SIRs along with decreasing absolute rates over the entire study period suggest that ovarian cancers in both the general population and survivors of breast cancer are declining in parallel, possibly because of common risk factor exposures. Analytic studies are needed to further assess the parallel overall trends and the age-specific interaction by ER expression.
PMCID: PMC3574269  PMID: 23284037
13.  Plasma markers of B-cell activation and clonality in pediatric liver and hematopoietic stem cell transplant recipients 
Transplantation  2013;95(3):519-526.
Transplant recipients are at risk of post-transplant lymphoproliferative disease (PTLD). Methods: Thirty-six pediatric transplant recipients were evaluated (18 hematopoietic stem cell and 18 liver recipients; 12 had PTLD). We studied 207 longitudinal plasma samples from these recipients for three markers of B-cell activation or clonality: immunoglobulin free light chains (FLCs), soluble CD30 (sCD30), and monoclonal immunoglobulins (M-proteins).
Kappa FLCs, lambda FLCs, and sCD30 were elevated in 20.8%, 28.0%, and 94.2% of plasma specimens, respectively. FLC and sCD30 levels increased significantly 1.18–1.82 fold per log10 Epstein Barr virus (EBV) load in peripheral blood. Five PTLD cases manifested elevated FLCs with an abnormal kappa/lambda ratio, suggesting monoclonal FLC production. M-proteins were present in 91% of PTLD cases, vs. 50–67% of other recipients with high or low EBV loads (p=0.13). Concordance of FLCs, M-proteins, and PTLD tumor light chain restriction was imperfect. For example, one PTLD case with an IgG lambda M-protein had a tumor that was kappa restricted, and another case with an M-protein had a T-cell PTLD. In an additional case, an IgM kappa M-protein and excess kappa FLCs were both detected in plasma at PTLD diagnosis; while the tumor was not restricted at diagnosis, kappa restriction was present 5 years later when the PTLD relapsed.
Plasma markers of B-cell dysfunction are frequent following transplantation and associated with poor EBV control. These abnormal markers may be produced by oligoclonal B-cell populations or PTLD tumor cells, and could potentially help identify recipients at high risk of PTLD.
PMCID: PMC3566275  PMID: 23222884
post transplant lymphoproliferative disease; Epstein-Barr virus (EBV); B cell; immune monitoring; immunoglobulins; cytokines
14.  Proportions of Kaposi Sarcoma, Selected Non-Hodgkin Lymphomas, and Cervical Cancer in the United States Occurring in Persons With AIDS, 1980–2007 
Given the higher risk of AIDS-defining malignancies that include Kaposi sarcoma (KS), certain non-Hodgkin lymphomas (NHLs), and cervical cancer in persons with human immunodeficiency virus (HIV) infection, the HIV epidemic has likely contributed to the overall numbers of these cancers in the United States.
To quantify the proportions of KS, AIDS-defining NHLs, and cervical cancer in the United States that occurred among persons with AIDS from 1980 to 2007.
Design, Setting, and Participants
The HIV/AIDS Cancer Match Study (1980–2007) linked data from 16 US HIV/AIDS and cancer registries to identify cases with and without AIDS for KS, AIDS-defining NHLs (ie, diffuse large B-cell lymphoma [DLBCL], Burkitt lymphoma [BL], and central nervous system [CNS] lymphoma), and cervical cancer. Using linked data, we derived cancer rates for persons with and without AIDS. To estimate national counts, the rates were applied to national AIDS surveillance and US Census data.
Main Outcome Measure
Proportion of AIDS-defining malignancies in the United States occurring in persons with AIDS.
In the United States, an estimated 79.0% (95% confidence interval [CI], 78.6%–79.4%) of 85 922 KS cases, 5.5% (95% CI, 5.3%–5.6%) of 383 095 DLBCL cases, 19.4% (95% CI, 17.8%–21.1%) of 17 780 BL cases, 26.2% (95% CI, 25.2%–27.1%) of 28 259 CNS lymphoma cases, and 0.41% (95% CI, 0.36%–0.46%) of 386 166 cervical cancer cases occurred among persons with AIDS during 1980–2007. The proportion of KS and AIDS-defining NHLs in persons with AIDS peaked in the early 1990s (1990–1995: KS, 89.0% [95%CI, 88.6%–89.3%]; DLBCL, 9.5% [95%CI, 9.2%–9.8%]; BL, 27.4% [95% CI, 25.0%–29.7%]; and CNS lymphoma, 47.2% [95% CI, 45.7%–48.7%]; all P<.001 [compared with 1980–1989]) and then declined (2001–2007: KS, 67.0% [95% CI, 64.5%–69.4%]; DLBCL, 4.3% [95% CI, 3.9%–4.6%]; BL, 20.8% [95% CI, 17.2%–24.3%]; and CNS lymphoma, 12.3% [95% CI, 10.1%–14.4%]; all P<.001 [compared with 1990–1995]). The proportion of cervical cancers in persons with AIDS increased overtime (1980–1989: 0.11% [95% CI, 0.08%–0.13%]; 2001–2007: 0.69% [95% CI, 0.49%–0.89%]; P<.001).
In the United States, the estimated proportions of AIDS-defining malignancies that occurred among persons with AIDS were substantial, particularly for KS and some NHLs. Except for cervical cancer, the proportions of AIDS-defining malignancies occurring among persons with AIDS peaked in the mid-1990s and then declined.
PMCID: PMC3909038  PMID: 21486978
15.  Absolute Risk Prediction of Second Primary Thyroid Cancer Among 5-Year Survivors of Childhood Cancer 
Journal of Clinical Oncology  2012;31(1):119-127.
We developed three absolute risk models for second primary thyroid cancer to assist with long-term clinical monitoring of childhood cancer survivors.
Patients and Methods
We used data from the Childhood Cancer Survivor Study (CCSS) and two nested case-control studies (Nordic CCSS; Late Effects Study Group). Model M1 included self-reported risk factors, model M2 added basic radiation and chemotherapy treatment information abstracted from medical records, and model M3 refined M2 by incorporating reconstructed radiation absorbed dose to the thyroid. All models were validated in an independent cohort of French childhood cancer survivors.
M1 included birth year, initial cancer type, age at diagnosis, sex, and past thyroid nodule diagnosis. M2 added radiation (yes/no), radiation to the neck (yes/no), and alkylating agent (yes/no). Past thyroid nodule was consistently the strongest risk factor (M1 relative risk [RR], 10.8; M2 RR, 6.8; M3 RR, 8.2). In the validation cohort, 20-year absolute risk predictions for second primary thyroid cancer ranged from 0.04% to 7.4% for M2. Expected events agreed well with observed events for each model, indicating good calibration. All models had good discriminatory ability (M1 area under the receiver operating characteristics curve [AUC], 0.71; 95% CI, 0.64 to 0.77; M2 AUC, 0.80; 95% CI, 0.73 to 0.86; M3 AUC, 0.75; 95% CI, 0.69 to 0.82).
We developed and validated three absolute risk models for second primary thyroid cancer. Model M2, with basic prior treatment information, could be useful for monitoring thyroid cancer risk in childhood cancer survivors.
PMCID: PMC3530689  PMID: 23169509
16.  Common obesity-related genetic variants and papillary thyroid cancer risk 
Epidemiologic studies have shown consistent associations between obesity and increased thyroid cancer risk, but, to date, no studies have investigated the relationship between thyroid cancer risk and obesity-related single nucleotide polymorphisms (SNPs).
We evaluated 575 tag SNPs in 23 obesity-related gene regions in a case-control study of 341 incident papillary thyroid cancer (PTC) cases and 444 controls of European ancestry. Logistic regression models, adjusted for attained age, year of birth, and sex were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) with SNP genotypes, coded as 0, 1, and 2 and modeled continuously to calculate P-trends.
Nine out of 10 top-ranking SNPs (Ptrend<0.01) were located in the FTO (fat mass and obesity associated) gene region, while the other was located in INSR (insulin receptor). None of the associations were significant after correcting for multiple testing.
Our data do not support an important role of obesity-related genetic polymorphisms in determining the risk of PTC.
Factors other than selected genetic polymorphisms may be responsible for the observed associations between obesity and increased PTC risk.
PMCID: PMC3518668  PMID: 23064004
single nucleotide polymorphisms; case-control study; obesity; body mass index; thyroid neoplasms
17.  Quantifying Cancer Absolute Risk and Cancer Mortality in the Presence of Competing Events after a Myotonic Dystrophy Diagnosis 
PLoS ONE  2013;8(11):e79851.
Recent studies show that patients with myotonic dystrophy (DM) have an increased risk of specific malignancies, but estimates of absolute cancer risk accounting for competing events are lacking. Using the Swedish Patient Registry, we identified 1,081 patients with an inpatient and/or outpatient diagnosis of DM between 1987 and 2007. Date and cause of death and date of cancer diagnosis were extracted from the Swedish Cause of Death and Cancer Registries. We calculated non-parametric estimates of absolute cancer risk and cancer mortality accounting for the high non-cancer competing mortality associated with DM. Absolute cancer risk after DM diagnosis was 1.6% (95% CI=0.4-4%), 5% (95% CI=3-9%) and 9% (95% CI=6-13%) at ages 40, 50 and 60 years, respectively. Females had a higher absolute risk of all cancers combined than males: 9% (95% CI=4-14), and 13% (95% CI=9-20) vs. 2% (95%CI= 0.7-6) and 4% (95%CI=2-8) by ages 50 and 60 years, respectively) and developed cancer at younger ages (median age =51 years, range=22-74 vs. 57, range=43-84, respectively, p=0.02). Cancer deaths accounted for 10% of all deaths, with an absolute cancer mortality risk of 2% (95%CI=1-4.5%), 4% (95%CI=2-6%), and 6% (95%CI=4-9%) by ages 50, 60, and 70 years, respectively. No gender difference in cancer-specific mortality was observed (p=0.6). In conclusion, cancer significantly contributes to morbidity and mortality in DM patients, even after accounting for high competing DM mortality from non-neoplastic causes. It is important to apply population-appropriate, validated cancer screening strategies in DM patients.
PMCID: PMC3827449  PMID: 24236163
18.  Impact of the HIV Epidemic on the Incidence Rates of Anal Cancer in the United States 
The risk of anal cancer is substantially increased in HIV-infected individuals. Thus, the HIV epidemic may have influenced the increasing anal cancer trends in the United States. We estimated the impact of the HIV epidemic on trends in anal cancer incidence in the United States during 1980–2005.
Data on anal cancer cases with and without AIDS were obtained from the HIV/AIDS Cancer Match Study. The number of HIV-infected anal cancer cases without AIDS was estimated from the number of anal cancers occurring before diagnosis of AIDS. The proportion of anal cancer cases with HIV infection in the general population was calculated. We estimated temporal trends in the incidence rates of anal cancer in the general population overall and after exclusion of HIV-infected cancer cases by calculating annual percent changes and 95% confidence intervals (CIs) using a Joinpoint log-linear model. All incidence rates were standardized to the 2000 US population by age, sex, and race.
During 1980–2005, of the 20 533 estimated anal cancer cases, 1665 (8.1%) were HIV-infected. During 2001–2005, the proportion of anal cancer cases with HIV infection was the highest—1.2% (95% CI = 0.93 to 1.4%) among females and 28.4% (95% CI = 26.6 to 29.4%) among males. During 1980–2005, HIV infection did not have an impact on the trends in anal cancer among females (incidence rates increased by 3.3% [95% CI = 3.0 to 3.7%] annually overall, and by 3.3% [95% CI = 2.9 to 3.6%] annually without HIV-infected anal cancer cases) but had a strong impact on the trends in anal cancer among males (incidence rates increased by 3.4% [95% CI = 2.9 to 3.9%] annually overall, and by 1.7% [95% CI = 1.2 to 2.3%] annually without HIV infection).
During 1980–2005, the increasing anal cancer incidence rates in the United States were strongly influenced by the HIV epidemic in males but were independent of HIV infection in females.
PMCID: PMC3611819  PMID: 23042932
19.  A variant upstream of IFNL3 (IL28B) creating a novel interferon gene IFNL4 is associated with impaired clearance of hepatitis C virus 
Nature genetics  2013;45(2):164-171.
Chronic infection with hepatitis C virus (HCV) is a common cause of liver cirrhosis and cancer. We performed RNA-sequencing in primary human hepatocytes activated with synthetic dsRNA to mimic HCV infection. Upstream of IFNL3 (IL28B) on chromosome 19q13.13, we discovered a novel, transiently induced region that harbors dinucleotide variant ss469415590 (TT/ΔG), which is in high linkage disequilibrium with rs12979860, a genetic marker strongly associated with HCV clearance. ss469415590-ΔG is a frame-shift variant that creates a novel primate-specific gene, designated interferon lambda 4 (IFNL4), which encodes a protein of moderate similarity with IFNL3. Compared to rs12979860, ss469415590 is more strongly associated with HCV clearance in individuals of African ancestry, whereas it provides comparable information in Europeans and Asians. Transient over-expression of IFNL4 in a hepatoma cell line induced STAT1/STAT2 phosphorylation and expression of interferon-stimulated genes. Our findings provide new insights into the genetic regulation of HCV clearance and its clinical management.
PMCID: PMC3793390  PMID: 23291588
21.  A variant in FTO shows association with melanoma risk not due to BMI 
Iles, Mark M | Law, Matthew H | Stacey, Simon N | Han, Jiali | Fang, Shenying | Pfeiffer, Ruth | Harland, Mark | MacGregor, Stuart | Taylor, John C | Aben, Katja K | Akslen, Lars A | Avril, Marie-Françoise | Azizi, Esther | Bakker, Bert | Benediktsdottir, Kristrun R | Bergman, Wilma | Scarrà, Giovanna Bianchi | Brown, Kevin M | Calista, Donato | Chaudru, Valerié | Fargnoli, Maria Concetta | Cust, Anne E | Demenais, Florence | de Waal, Anne C | Dębniak, Tadeusz | Elder, David E | Friedman, Eitan | Galan, Pilar | Ghiorzo, Paola | Gillanders, Elizabeth M | Goldstein, Alisa M | Gruis, Nelleke A | Hansson, Johan | Helsing, Per | Hočevar, Marko | Höiom, Veronica | Hopper, John L | Ingvar, Christian | Janssen, Marjolein | Jenkins, Mark A | Kanetsky, Peter A | Kiemeney, Lambertus A | Lang, Julie | Lathrop, G Mark | Leachman, Sancy | Lee, Jeffrey E | Lubiński, Jan | Mackie, Rona M | Mann, Graham J | Mayordomo, Jose I | Molven, Anders | Mulder, Suzanne | Nagore, Eduardo | Novaković, Srdjan | Okamoto, Ichiro | Olafsson, Jon H | Olsson, Håkan | Pehamberger, Hubert | Peris, Ketty | Grasa, Maria Pilar | Planelles, Dolores | Puig, Susana | Puig-Butille, Joan Anton | Randerson-Moor, Juliette | Requena, Celia | Rivoltini, Licia | Rodolfo, Monica | Santinami, Mario | Sigurgeirsson, Bardur | Snowden, Helen | Song, Fengju | Sulem, Patrick | Thorisdottir, Kristin | Tuominen, Rainer | Van Belle, Patricia | van der Stoep, Nienke | van Rossum, Michelle M | Wei, Qingyi | Wendt, Judith | Zelenika, Diana | Zhang, Mingfeng | Landi, Maria Teresa | Thorleifsson, Gudmar | Bishop, D Timothy | Amos, Christopher I | Hayward, Nicholas K | Stefansson, Kari | Bishop, Julia A Newton | Barrett, Jennifer H
Nature genetics  2013;45(4):428-432.
We report the results of an association study of melanoma based on the genome-wide imputation of the genotypes of 1,353 cases and 3,566 controls of European origin conducted by the GenoMEL consortium. This revealed a novel association between several single nucleotide polymorphisms (SNPs) in intron 8 of the FTO gene, including rs16953002, which replicated using 12,313 cases and 55,667 controls of European ancestry from Europe, the USA and Australia (combined p=3.6×10−12, per-allele OR for A=1.16). As well as identifying a novel melanoma susceptibility locus, this is the first study to identify and replicate an association with SNPs in FTO not related to body mass index (BMI). These SNPs are not in intron 1 (the BMI-related region) and show no association with BMI. This suggests FTO’s function may be broader than the existing paradigm that FTO variants influence multiple traits only through their associations with BMI and obesity.
PMCID: PMC3640814  PMID: 23455637
22.  Cell-Cycle Control in Urothelial Carcinoma: Large-scale Tissue Array Analysis of Tumor Tissue from Maine and Vermont 
Cell-cycle proteins are important predictive markers in urothelial carcinoma but may also exhibit exposure-specific heterogeneity.
Tumor tissue from 491 bladder cancer cases enrolled in the Maine and Vermont component of the New England Bladder Cancer Study was assembled as tissue microarrays and examined for aberrant expression of p53, p63, p16, cyclin D1, Rb, and Ki-67. The association between expression and histopathology, demographics, and cigarette smoking was examined using χ2 tests, multivariable Poisson, and multinomial regression models.
We found that overexpression of p53 and Ki-67 was associated with high-stage/grade tumors [relative risk (RR), 1.26; Ptrend = 0.003; and RR, 3.21; Ptrend < 0.0001, respectively], whereas expression of p63 and p16 was decreased in high-stage/grade tumors (RR, 0.52; Ptrend < 0.0001; and RR, 0.88; Ptrend = 0.04, respectively). No significant aberrations of cell-cycle proteins were identified using various smoking variables and multiple statistical models.
The results of this population-based study of histologically confirmed urothelial carcinomas show significant aberration of cell-cycle proteins p53, p63, p16, and Ki-67, but not Rb or cyclin D1. p53 showed the most significant heterogeneity with respect to tumor stage and grade, especially when stratified for different staining intensities using novel digital image analysis techniques. Our findings do not support that smoking modifies expression of cell-cycle proteins.
Our study shows significant heterogeneity in the expression of key cell-cycle proteins that are associated with disease progression in bladder cancer. Further studies may lead to the identification of biomarkers and their multiplexed interactions as useful prognostic and therapeutic targets.
PMCID: PMC3480660  PMID: 22761304
23.  Estrogen metabolism and mammographic density in postmenopausal women: a cross-sectional study 
Prospective studies have consistently found that postmenopausal breast cancer risk increases with circulating estrogens; however, findings from studies of estrogens and mammographic density (MD), an intermediate marker of breast cancer risk, have been inconsistent. We investigated the cross-sectional associations of urinary estrogens, and their 2-, 4-, and 16-hydroxylated metabolites with MD.
Postmenopausal women without breast cancer (n=194), ages 48-82 years, and reporting no current menopausal hormone therapy use were enrolled at a clinic in Western NY in 2005. Urinary estrogens and estrogen metabolites were measured using mass spectrometry. Percent MD and dense area (cm2) were measured using computer-assisted analyses of digitized films. Linear regression models were used to estimate associations of log-transformed estrogen measures with MD while adjusting for age, body mass index (BMI), parity, and past hormone therapy use.
Urinary concentrations of most individual estrogens and metabolites were not associated with MD; however, across the interdecile range of the ratio of parent estrogens (estrone and estradiol) to their metabolites, MD increased by 6.8 percentage points (p=0.02) and dense area increased by 10.3 cm2 (p=0.03). Across the interdecile ranges of the ratios of 2-, 4-, and 16-hydroxylation pathways to the parent estrogens, MD declined by 6.2 (p=0.03), 6.4 (p=0.04), and 5.7 (p=0.05) percentage points, respectively. All associations remained apparent in models without adjustment for BMI.
In this study of postmenopausal women, less extensive hydroxylation of parent estrogens was associated with higher MD.
Hydroxylation of estrogens may modulate postmenopausal breast cancer risk through a pathway involving MD.
PMCID: PMC3436977  PMID: 22736791
Estrogens; metabolism; mammography; breast neoplasms; risk factors; human; female; middle-aged
24.  Telomere Length and the Risk of Cutaneous Malignant Melanoma in Melanoma-Prone Families with and without CDKN2A Mutations 
PLoS ONE  2013;8(8):e71121.
Recent evidence suggests a link between constitutional telomere length (TL) and cancer risk. Previous studies have suggested that longer telomeres were associated with an increased risk of melanoma and larger size and number of nevi. The goal of this study was to examine whether TL modified the risk of melanoma in melanoma-prone families with and without CDKN2A germline mutations.
Materials and Methods
We measured TL in blood DNA in 119 cutaneous malignant melanoma (CMM) cases and 208 unaffected individuals. We also genotyped 13 tagging SNPs in TERT.
We found that longer telomeres were associated with an increased risk of CMM (adjusted OR = 2.81, 95% CI = 1.02–7.72, P = 0.04). The association of longer TL with CMM risk was seen in CDKN2A- cases but not in CDKN2A+ cases. Among CMM cases, the presence of solar injury was associated with shorter telomeres (P = 0.002). One SNP in TERT, rs2735940, was significantly associated with TL (P = 0.002) after Bonferroni correction.
Our findings suggest that TL regulation could be variable by CDKN2A mutation status, sun exposure, and pigmentation phenotype. Therefore, TL measurement alone may not be a good marker for predicting CMM risk.
PMCID: PMC3747185  PMID: 23990928
25.  Quality Assessment of Microarray Data in a Multicenter Study 
Issues implicit in a multicenter microarray study are protocol standardization and monitoring center adherence to established protocols. This study explored the effects of submitting center and sample preservation method on the quality of isolated RNA. In addition, the effects of sample preservation method and laboratory on microarray quality were also examined. Herein we evaluated the contribution of specific technical factors [center, laboratory, and preservation method (frozen/RNAlater)] on quality of isolated RNA, cRNA synthesis products, and reproducibility of gene expression microarray data for independent biologic samples collected in a multicenter microarray study. The Kruskal-Wallis test was used to test for differences owing to submitting center on isolated RNA quality. Mixed effects analysis of variance was used in assessing the impact of laboratory and preservation method on gene expression values for the 12 samples hybridized at 2 independent laboratories (24 GeneChips). One center was found to be in violation of the tissue handling protocol. No significant effect was noted owing to preservation method, which ensured that our tissue handling protocols are working properly. There was a significant laboratory effect with respect to cRNA yield, though this effect did not impact sample quality. We conclude that use of consistent protocols for sample collection, RNA extraction, cDNA/cRNA synthesis, labeling, hybridization, platform, image acquisition, normalization, and expression summaries can yield consistent expression values. Moreover, evaluation of sample quality at various steps in the data acquisition process is an important component of a multicenter study to ensure all participating centers adhere to established protocols.
PMCID: PMC3738008  PMID: 19214110
microarray; multicenter study; gene expression; Affymetrix GeneChip; quality

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