A genetic component is well established in the etiology of breast cancer. It is not well known, however, whether genetic traits also influence prognostic features of the malignant phenotype.
We carried out a population-based cohort study in Sweden based on the nationwide Multi-Generation Register. Among all women with breast cancer diagnosed from 1961 to 2001, 2,787 mother-daughter pairs and 831 sister pairs with breast cancer were identified; we achieved complete follow-up and classified 5-year breast cancer-specific prognosis among proband (mother or oldest sister) into tertiles as poor, intermediary, or good. We used Kaplan-Meier estimates of survival proportions and Cox models to calculate relative risks of dying from breast cancer within 5 years depending on the proband's outcome.
The 5-year survival proportion among daughters whose mothers died within 5 years was 87% compared to 91% if the mother was alive (p = 0.03). Among sisters, the corresponding proportions were 70% and 88%, respectively (p = 0.001). After adjustment for potential confounders, daughters and sisters of a proband with poor prognosis had a 60% higher 5-year breast cancer mortality compared to those of a proband with good prognosis (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.2 to 2.2; p for trend 0.002). This association was slightly stronger among sisters (HR, 1.8; 95% CI, 1.0 to 3.4) than among daughters (HR, 1.6; 95% CI, 1.1 to 2.3).
Breast cancer prognosis of a woman predicts the survival in her first-degree relatives with breast cancer. Our novel findings suggest that breast cancer prognosis might be inherited.
To determine whether consumption of whole-grain; rye bread, oatmeal, and whole-wheat bread, during different periods of life, is associated with risk of prostate cancer (PCa).
In 2002 to 2006, 2,268 men, aged 67-96 years, reported their dietary habits in the AGES-Reykjavik cohort study. Dietary habits were assessed for early-, mid- , and current life using a validated food frequency questionnaire (FFQ). Through linkage to cancer- and mortality registers, we retrieved information on PCa diagnosis and mortality through 2009. We used regression models to estimate odds ratios (ORs) and hazard ratios (HRs) for PCa according to whole grain consumption, adjusted for possible confounding factors including fish-, fish liver oil-, meat-, and milk intake.
Of the 2,268 men, 347 had or were diagnosed with PCa during follow-up, 63 with advanced disease (stage 3+ or died of PCa). Daily rye bread consumption in adolescence (vs. less than daily) was associated with a decreased risk of PCa diagnosis (OR = 0.76, 95% Confidence interval (CI): 0.59-0.98), and of advanced PCa (OR = 0.47, 95% CI: 0.27-0.84). High intake of oatmeal in adolescence (≥5 vs. ≤4 times/ week) was not significantly associated with risk of PCa diagnosis (OR = 0.99, 95% CI: 0.77-1.27) nor advanced PCa (OR = 0.67, 95% CI: 0.37-1.20). Mid-, and late life consumption of rye bread, oatmeal, or whole-wheat bread was not associated with PCa risk.
Our results suggest that rye bread consumption in adolescence may be associated with reduced risk of PCa, particularly advanced disease.
adolescent; diet; epidemiology; rye bread; prostatic neoplasms; whole-grain; AGES Reykjavik study
Accumulating evidence suggests that risk factors for classical Hodgkin lymphoma (cHL) differ by tumor Epstein–Barr virus (EBV) status. This potential etiological heterogeneity is not recognized in current disease classification.
We conducted a genome-wide association study of 1200 cHL patients and 6417 control subjects, with validation in an independent replication series, to identify common genetic variants associated with total cHL and subtypes defined by tumor EBV status. Multiple logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) assuming a log-additive genetic model for the variants. All statistical tests were two-sided.
Two novel loci associated with total cHL irrespective of EBV status were identified in the major histocompatibility complex region; one resides adjacent to MICB (rs2248462: OR = 0.61, 95% CI = 0.53 to 0.69, P = 1.3 × 10−13) and the other at HLA-DRA (rs2395185: OR = 0.56, 95% CI = 0.50 to 0.62, P = 8.3 × 10−25) with both results confirmed in an independent replication series. Consistent with previous reports, associations were found between EBV-positive cHL and genetic variants within the class I region (rs2734986, HLA-A: OR = 2.45, 95% CI = 2.00 to 3.00, P = 1.2 × 10−15; rs6904029, HCG9: OR = 0.46, 95% CI = 0.36 to 0.59, P = 5.5 × 10−10) and between EBV-negative cHL and rs6903608 within the class II region (rs6903608, HLA-DRA: OR = 2.08, 95% CI = 1.84 to 2.35, P = 6.1 × 10−31). The association between rs6903608 and EBV-negative cHL was confined to the nodular sclerosis histological subtype. Evidence for an association between EBV-negative cHL and rs20541 (5q31, IL13: OR = 1.53, 95% CI = 1.32 to 1.76, P = 5.4 x 10−9), a variant previously linked to psoriasis and asthma, was observed; however, the evidence for replication was less clear. Notably, one additional psoriasis-associated variant, rs27524 (5q15, ERAP1), showed evidence of an association with cHL in the genome-wide association study (OR = 1.21, 95% CI = 1.10 to 1.33, P = 1.5 × 10−4) and replication series (P = .03).
Overall, these results provide strong evidence that EBV status is an etiologically important classification of cHL and also suggest that some components of the pathological process are common to both EBV-positive and EBV-negative patients.
High serum levels of macrophage inhibitory cytokine 1 (MIC-1) are strongly associated with metastatic prostate cancer, suggesting MIC-1 is a biomarker for prostate cancer prognosis.
We conducted a prospective cohort study of 1,442 Swedish men with a pathologically verified diagnosis of prostate cancer between 2001 and 2003. Blood was drawn either pretreatment (n = 431) or posttreatment (n = 1,011) and cases were followed for a mean time of 4.9 years (range, 0.1–6.8 years).
MIC-1 serum levels independently predicted poor cancer-specific survival with an almost 3-fold higher cancer death rate in patients with serum levels in the highest quartile compared with men with serum levels in the lowest quartile (adjusted hazard ratio, 2.98; 95% confidence interval, 1.82–4.68). Pretreatment MIC-1 levels revealed an even stronger association with disease outcome with an 8-fold higher death rate in the highest compared with the lowest category (adjusted hazard ratio, 7.98; 95% confidence interval, 1.73–36.86). Among patients considered to have localized disease, MIC-1 significantly increased the discriminative capacity between indolent and lethal prostate cancer compared with the established prognostic markers clinical stage, pathologic grade, and prostate-specific antigen level (P = 0.016). A sequence variant in the MIC-1 gene was associated with decreased MIC-1 serum levels (P = 0.002) and decreased prostate cancer mortality (P = 0.003), suggesting a causative role of MIC-1 in prostate cancer prognosis.
Serum MIC-1 concentration is a novel biomarker capable of predicting prostate cancer prognosis.
The authors investigated whether early-life residency in certain areas of Iceland marked by distinct differences in milk intake was associated with risk of prostate cancer in a population-based cohort of 8,894 men born between 1907 and 1935. Through linkage to cancer and mortality registers, the men were followed for prostate cancer diagnosis and mortality from study entry (in waves from 1967 to 1987) through 2009. In 2002–2006, a subgroup of 2,268 participants reported their milk intake in early, mid-, and current life. During a mean follow-up period of 24.3 years, 1,123 men were diagnosed with prostate cancer, including 371 with advanced disease (stage 3 or higher or prostate cancer death). Compared with early-life residency in the capital area, rural residency in the first 20 years of life was marginally associated with increased risk of advanced prostate cancer (hazard ratio = 1.29, 95% confidence interval (CI): 0.97, 1.73), particularly among men born before 1920 (hazard ratio = 1.64, 95% CI: 1.06, 2.56). Daily milk consumption in adolescence (vs. less than daily), but not in midlife or currently, was associated with a 3.2-fold risk of advanced prostate cancer (95% CI: 1.25, 8.28). These data suggest that frequent milk intake in adolescence increases risk of advanced prostate cancer.
adolescent; diet; Iceland; milk; prostatic neoplasms; risk factors
Causes of the rapidly increasing incidence of breast cancer in Middle East and Asian countries are incompletely understood. We evaluated risk factors for postmenopausal breast cancer and estimated their attributable fraction in Iran.
We performed a hospital-based case–control study, including 493 women, diagnosed with breast cancer at 50 years or later between 2005–2008, and 493 controls. We used logistic regression models to estimate multivariable odds ratios (OR) and 95% confidence intervals (CI), and population attributable fractions (PAF) for significant risk factors.
The risk of breast cancer decreased with increasing parity. Compared with nulliparous women, the adjusted OR (95% CI) was 0.53 (0.25-1.15) for parity 1–3, 0.47 (0.29-0.93) for parity 4–6 and 0.23 (0.11-0.50) for parity ≥7. The estimated PAF for parity (<7) was 52%. The positive association between body mass index (BMI) and breast cancer risk was confined to women diagnosed at 58 years or later. Compared with normal weight women (BMI 18.5-24.9), overweight (BMI 25–29.9) and obese (BMI ≥30) women were at increased risk of breast cancer diagnosed at 58 years or later (ORs [95% CI] 1.27 [0.97-2.65] and 2.34 [1.33-4.14], respectively). The estimated PAF for obesity/overweight (BMI >25) was approximately 25%. The family history was significantly associated with increased breast cancer risk, but not increasing height, early age at menarche, late age at first birth or short breastfeeding.
Decreasing parity and increasing obesity are determinants of increasing breast cancer incidence among Iranian women. These trends predict a continuing upward trend of postmenopausal breast cancer.
Breast neoplasm; Postmenopausal; Middle East; Risk factor; Attributable fraction
Prostate-specific antigen screening has led to enormous overtreatment of prostate cancer because of the inability to distinguish potentially lethal disease at diagnosis. We reasoned that by identifying an mRNA signature of Gleason grade, the best predictor of prognosis, we could improve prediction of lethal disease among men with moderate Gleason 7 tumors, the most common grade, and the most indeterminate in terms of prognosis.
Patients and Methods
Using the complementary DNA–mediated annealing, selection, extension, and ligation assay, we measured the mRNA expression of 6,100 genes in prostate tumor tissue in the Swedish Watchful Waiting cohort (n = 358) and Physicians' Health Study (PHS; n = 109). We developed an mRNA signature of Gleason grade comparing individuals with Gleason ≤ 6 to those with Gleason ≥ 8 tumors and applied the model among patients with Gleason 7 to discriminate lethal cases.
We built a 157-gene signature using the Swedish data that predicted Gleason with low misclassification (area under the curve [AUC] = 0.91); when this signature was tested in the PHS, the discriminatory ability remained high (AUC = 0.94). In men with Gleason 7 tumors, who were excluded from the model building, the signature significantly improved the prediction of lethal disease beyond knowing whether the Gleason score was 4 + 3 or 3 + 4 (P = .006).
Our expression signature and the genes identified may improve our understanding of the de-differentiation process of prostate tumors. Additionally, the signature may have clinical applications among men with Gleason 7, by further estimating their risk of lethal prostate cancer and thereby guiding therapy decisions to improve outcomes and reduce overtreatment.
Recent genome-wide association studies have been successful in identifying common sequence variants associated with prostate cancer risk; however, their importance in prostate cancer prognosis remains unknown. To assess confirmed prostate cancer susceptibility variants with prostate cancer prognosis, we genotyped 16 established susceptibility variants in a Swedish cohort of 2,875 prostate cancer cases, ascertained between 2001 and 2003, with complete follow-up regarding vital status through January 2008. Cox regression models, adjusted for age, clinical stage, pathologic grade, nodal or distant metastases, and diagnostic serum levels of prostate-specific antigen level, were used to assess association between risk variants and prostate cancer–specific survival. During follow-up, 626 men died, and of those, 440 had prostate cancer classified as their underlying cause of death. We found no association between any of the explored sequence variants and prostate cancer–specific mortality, either in exploring individual variants or in assessing the cumulative effect of all variants. We conclude that hitherto established prostate cancer susceptibility variants are not associated with the lethal potential of prostate cancer.
Prostate specific antigen (PSA) is widely used for prostate cancer screening but its levels are influenced by many non cancer-related factors. The goal of the study is to estimate the effect of genetic variants on PSA levels.
We evaluated the association of SNPs that were reported to be associated with prostate cancer risk in recent genome-wide association studies with plasma PSA levels in a Swedish study population, including 1,722 control subjects without a diagnosis of prostate cancer.
Of the 16 SNPs analyzed in control subjects, significant associations with PSA levels (P≤0.05) were found for six SNPs. These six SNPs had a cumulative effect on PSA levels; the mean PSA levels in men were almost twofold increased across increasing quintile of number of PSA associated alleles, P-trend=3.4×10−14. In this Swedish study population risk allele frequencies were similar among T1c case patients (cancer detected by elevated PSA levels alone) as compared to T2 and above prostate cancer case patients.
Results from this study may have two important clinical implications. The cumulative effect of six SNPs on PSA levels suggests genetic-specific PSA cutoff values may be used to improve the discriminatory performance of this test for prostate cancer; and the dual associations of these SNPs with PSA levels and prostate cancer risk raise a concern that some of reported prostate cancer risk-associated SNPs may be confounded by the prevalent use of PSA screening.
genetic; bias; KLK3
The burden of breast cancer in Asia is escalating. We evaluated the impact of ethnicity on survival after breast cancer in the multi-ethnic region of South East Asia.
Using the Singapore-Malaysia hospital-based breast cancer registry, we analyzed the association between ethnicity and mortality following breast cancer in 5,264 patients diagnosed between 1990 and 2007 (Chinese: 71.6%, Malay: 18.4%, Indian: 10.0%). We compared survival rates between ethnic groups and calculated adjusted hazard ratios (HR) to estimate the independent effect of ethnicity on survival. Malays (n = 968) presented at a significantly younger age, with larger tumors, and at later stages than the Chinese and Indians. Malays were also more likely to have axillary lymph node metastasis at similar tumor sizes and to have hormone receptor negative and poorly differentiated tumors. Five year overall survival was highest in the Chinese women (75.8%; 95%CI: 74.4%–77.3%) followed by Indians (68.0%; 95%CI: 63.8%–72.2%), and Malays (58.5%; 95%CI: 55.2%–61.7%). Compared to the Chinese, Malay ethnicity was associated with significantly higher risk of all-cause mortality (HR: 1.34; 95%CI: 1.19–1.51), independent of age, stage, tumor characteristics and treatment. Indian ethnicity was not significantly associated with risk of mortality after breast cancer compared to the Chinese (HR: 1.14; 95%CI: 0.98–1.34).
In South East Asia, Malay ethnicity is independently associated with poorer survival after breast cancer. Research into underlying reasons, potentially including variations in tumor biology, psychosocial factors, treatment responsiveness and lifestyle after diagnosis, is warranted.
A fine mapping study in the HNF1B gene at 17q12 among two study populations revealed a second prostate cancer locus, ~26 kb centromeric to the first known locus (rs4430796); these are separated by a recombination hotspot. A SNP in the second locus (rs11649743) was confirmed in five additional populations, and P=1.7×10−9 for an allelic test in the seven combined studies. The association at each SNP remains significant after adjusting for the other SNP.
While PSA is the best biomarker for predicting prostate cancer, its predictive performance needs to be improved. Results from the Prostate Cancer Prevention Trial (PCPT) revealed the overall performance measured by the areas under curve (AUC) of the receiver operating characteristic (ROC) at 0.68. The goal of the present study is to assess the ability of genetic variants as a PSA independent method to predict prostate cancer risk.
We systematically evaluated all prostate cancer risk variants that were identified from genome-wide association studies during the past year in a large population-based prostate cancer case-control study population in Sweden, including 2,893 prostate cancer patients and 1,781 men without prostate cancer.
Twelve SNPs were independently associated with prostate cancer risk in this Swedish study population. Using a cutoff of any 11 risk alleles or family history, the sensitivity and specificity for predicting prostate cancer were 0.25 and 0.86, respectively. The overall predictive performance of prostate cancer using genetic variants, family history, and age, measured by AUC was 0.65 (95% CI: 0.63–0.66), significantly improved over that of family history and age (0.61%, 95% CI: 0.59–0.62), P = 2.3 × 10−10.
The predictive performance for prostate cancer using genetic variants and family history is similar to that of PSA. The utility of genetic testing, alone and in combination with PSA levels, should be evaluated in large studies such as the European Randomized Study for Prostate Cancer trial and PCPT.
prostate cancer; prediction; PSA; association
The link between squamous cell cervical carcinoma and HPV 16/18 is well-established but the magnitude of the risk association is uncertain and the importance of other high-risk HPV types unclear.
In two prospective nested case-control series among women participating in cytological screening in Sweden, we collected 2772 cervical smears from 515 women with cancer in situ (CIS), 315 with invasive squamous cell carcinoma (SCC), and individually matched controls. All smears were tested for HPV with PCR assays and the median follow-up until diagnosis was 5-7 years. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI).
Presence of HPV16/18 in the first smear was associated with 8.5-fold (95% CI 5.3-13.7), and 18.6-fold (95% CI 9.0-38.9) increased risks of CIS and SCC, respectively, compared to women negative for HPV. Infection with other high-risk HPV types in the first smear was also associated with significantly increased risks for both CIS and SCC. Persistence of HPV16 infection conferred a RR of 18.5 (95% CI, 6.5-52.9) for CIS and 19.5 (95% CI 4.7-81.7) for SCC. The HPV16/18 attributable risk proportion was estimated to 30-50% of CIS, and 41-47% of SCC. Other high-risk HPV types also conferred significant proportions.
Our large population-based study provides quantification of risks for different HPV types and prospective evidence that non-16/18 high-risk HPV types increase the risk for future cervical cancer.
This study gives further insights into cervical cancer risk stratification with implications for HPV-based prevention strategies.
Cervical cancer; HPV; risk; prevalence; persistence
Incidence of prostate cancer (PCa) has greatly increased in the Nordic region over the past two decades, following the advent of prostate-specific antigen (PSA) screening. Consequently, interpreting temporal trends in PCa has become difficult, and the impact of changes in exposure to causal factors is uncertain.
To reveal geographic differences and temporal trends in PCa in the Nordic countries. Because the recorded incidence of PCa has been profoundly influenced by PSA screening, we focused our analyses primarily on PCa mortality.
Design, setting, and participants
We analyzed national PCa incidence and mortality data from Denmark, Finland, Norway, and Sweden from 1965 to 2006 using the PC-NORDCAN software program and the online NORDCAN database.
Cumulative incidence and cumulative mortality from PCa were calculated for selected calendar years during four decades, along with age-standardized mortality rates. Incidence data in NORDCAN come from individual countries’ cancer registries, and mortality data come from national mortality registries.
Results and limitations
From 1965 to 2006, 172 613 deaths from PCa were reported in the four Nordic countries. A substantial rise in incidence was observed across the region, with some geographic variation, since the late 1980s. In contrast, both disease-specific mortality rates and cumulative risk of PCa mortality lacked consistent temporal trends over the same period. Cumulative risk of PCa mortality ranged between 3.5% and 7.5% in the region over four decades, whereas cumulative incidence jumped from about 9% to >20%. Mortality has remained fairly constant among the countries, with a minimally lower risk in Finland.
Unlike most malignancies, the occurrence of lethal PCa showed minimal geographic variation and lacked consistent temporal trends over four decades. These findings may guide our search for important causes of PCa, a malignancy with etiology that is still largely unknown.
Cancer trends; Mortality; Nordic region; Prostate cancer
It has been recently reported that expression of estrogen alpha (ER-α) and progesterone (PR) receptors in the normal mammary gland is inversely associated with breast cancer risk among postmenopausal women. We investigated whether dietary intakes are associated with the expression of ER-α and PR receptors in the apparently normal, as opposed to pathological, mammary tissue.
In a study in Greece, we examined associations of dietary intakes with ER-α and PR expression in the adjacent-to-pathological apparently normal mammary tissue of 562 women with either breast cancer (267 women) or BBD (299 women). Diet was assessed through an extensive food frequency questionnaire and results were analyzed using multiple logistic regression.
Monounsaturated (p=0.03) and, to a lesser extent, polyunsaturated lipids (p=0.08) were positively associated with ER-α expression. Cereals and starchy roots were inversely associated with ER-α (p=0.01), whereas milk and dairy products were inversely associated with PR expression (p=0.02). Ethanol intake was non-significantly inversely associated with ER-α expression (p=0.07).
Our findings suggest that the weak associations of diet with breast cancer risk could be explained, to some extent, by effects of diet on receptor expression in the normal mammary gland.
breast cancer; estrogen receptor; progesterone receptor; mammary tissue
Historically, toxicology has played a significant role in verifying conclusions drawn on the basis of epidemiological findings. Agents that were suggested to have a role in human diseases have been tested in animals to firmly establish a causative link. Bacterial pathogens are perhaps the oldest examples, and tobacco smoke and lung cancer and asbestos and mesothelioma provide two more recent examples. With the advent of toxicity testing guidelines and protocols, toxicology took on a role that was intended to anticipate or predict potential adverse effects in humans, and epidemiology, in many cases, served a role in verifying or negating these toxicological predictions. The coupled role of epidemiology and toxicology in discerning human health effects by environmental agents is obvious, but there is currently no systematic and transparent way to bring the data and analysis of the two disciplines together in a way that provides a unified view on an adverse causal relationship between an agent and a disease. In working to advance the interaction between the fields of toxicology and epidemiology, we propose here a five-step “Epid-Tox” process that would focus on: (1) collection of all relevant studies, (2) assessment of their quality, (3) evaluation of the weight of evidence, (4) assignment of a scalable conclusion, and (5) placement on a causal relationship grid. The causal relationship grid provides a clear view of how epidemiological and toxicological data intersect, permits straightforward conclusions with regard to a causal relationship between agent and effect, and can show how additional data can influence conclusions of causality.
epidemiology; causation; framework
The majority of prostate cancers harbor gene fusions of the 5′-untranslated region of the androgen-regulated transmembrane protease, serine 2 (TMPRSS2) promoter with erythroblast transformation specific (ETS) transcription factor family members. The common v-ets erythroblastosis virus E26 oncogene homolog [avian] (TMPRSS2–ERG) fusion is associated with a more aggressive clinical phenotype, implying the existence of a distinct subclass of prostate cancer defined by this fusion.
We used cDNA-mediated annealing, selection, ligation, and extension to determine the expression profiles of 6144 transcriptionally informative genes in archived biopsy samples from 455 prostate cancer patients in the Swedish Watchful Waiting cohort (1987–1999) and the US-based Physicians Health Study cohort (1983–2003). A gene expression signature for prostate cancers with the TMPRSS2-ERG fusion was determined using partitioning and classification models and used in computational functional analysis. Cell proliferation and TMPRSS2-ERG expression in androgen receptor–negative (NCI-H660) and –positive (VCaP-ERβ) prostate cancer cells after treatment with vehicle or estrogenic compounds were assessed by viability assays and quantitative polymerase chain reaction, respectively. All statistical tests were two-sided.
We identified an 87-gene expression signature that distinguishes TMPRSS2-ERG fusion prostate cancer as a discrete molecular entity (area under the curve = 0.80, 95% confidence interval [CI] = 0.792 to 0.81; P<.001). Computational analysis suggested that this fusion signature was associated with estrogen receptor (ER) signaling. Viability of NCI-H660 cells decreased after treatment with estrogen (viability normalized to day 0, estrogen vs vehicle at day 8, mean = 2.04 vs 3.40, difference = 1.36, 95% CI = 1.12 to 1.62) or ERβ agonist (ERβ agonist vs vehicle at day 8, mean = 1.86 vs 3.40, difference = 1.54, 95% CI = 1.39 to 1.69) but increased after ERα agonist treatment (ERα agonist vs vehicle at day 8, mean = 4.36 vs 3.40, difference = 0.96, 95% CI = 0.68 to 1.23). Similarly, expression of TMPRSS2-ERG decreased after ERβ agonist treatment (fold change over internal control, ERβ agonist vs vehicle at 24 hours, NCI H660, mean = 0.57-fold vs 1.0-fold, difference = 0.43, 95% CI = 0.29-fold to 0.57-fold) and increased after ERα agonist treatment (ERα agonist vs vehicle at 24 hours, mean = 5.63-fold vs 1.0-fold, difference = 4.63-fold, 95% CI = 4.34-fold to 4.92-fold).
TMPRSS2-ERG fusion prostate cancer is a distinct molecular subclass. TMPRSS2-ERG expression is regulated by a novel ER-dependent mechanism.
To identify susceptibility loci for non-Hodgkin lymphoma (NHL) subtypes, we conducted a three-stage genome-wide association study. We identified two variants associated with follicular lymphoma (FL) in 1,465 FL cases/6,958 controls at 6p21.32 (rs10484561, rs7755224, r2=1.0; combined p-values=1.12×10-29, 2.00×10-19), providing further support that MHC genetic variation influences FL susceptibility. Confirmatory evidence of a previously reported association was also found between chronic lymphocytic leukemia/small lymphocytic lymphoma and rs735665 (combined p-value=4.24×10-9).
Human papillomaviruses (HPV) are established as a major cause of cervical carcinoma. However, causality inference is dependent on prospective evidence showing that exposure predicts risk for future disease. Such evidence is available for squamous cell carcinoma, but not for cervical adenocarcinoma. We followed a population-based cohort of 994 120 women who participated in cytological screening in Sweden for a median of 6.7 years. Baseline smears from women who developed adenocarcinoma during follow-up (118 women with in situ disease and 164 with invasive disease) and their individually matched controls (1434 smears) were analyzed for HPV using PCR. Conditional logistic regression was used to estimate odds ratios (OR) of future adenocarcinoma with 95% confidence intervals (CI). Being positive for HPV 16 in the first cytologically normal smear was associated with increased risks for both future adenocarcinoma in situ (OR 11.0, 95 % CI 2.6–46.8) and invasive adenocarcinoma (OR 16.0, 95 % CI 3.8–66.7), compared to being negative for HPV 16. Similarly, an HPV 18 positive smear was associated with increased risks for adenocarcinoma in situ (OR 26.0, 95 % CI 3.5–192) and invasive adenocarcinoma (OR 28.0, 95 % CI 3.8–206), compared to an HPV 18 negative smear. Being positive for HPV 16/18 in two subsequent smears was associated with an infinite risk of both in situ and invasive adenocarcinoma. In conclusion, infections with HPV 16 and 18 are detectable up to at least 14 years before diagnosis of cervical adenocarcinoma. Our data provide prospective evidence that the association of HPV16/18 with cervical adenocarcinoma is strong and causal.
Adenocarcinoma; adenocarcinoma in situ; HPV; cervical cancer; prospective
To investigate whether intake of fruits and vegetables is associated with overall cancer incidence in a large prospective cohort of women in Sweden characterised by young age at enrolment (30–49 years) and relatively low intake of fruits and vegetables.
We followed prospectively 49,261 women, who completed a food frequency questionnaire in 1991–1992. A total of 2,347 incident invasive cancer cases were identified until December 2006. The occurrence of cancer was analysed by fitting Poisson regression models, estimating incidence rate ratios (RR) and 95% confidence intervals (CI).
The median intake of fruits and vegetables was 204 g/day (10th; 90th percentile: 37; 564 g/day). Intake of fruits and vegetables was not statistically significantly associated with overall cancer incidence. When we compared women in the highest quintile of fruit and vegetable intake to women in the lowest quintile, the RR for overall cancer was 1.01 (95% CI: 0.88–1.16). Similar results were obtained when investigating the effect of intake of fruits and vegetables separately and when we stratified women by age at follow-up.
Fruit and vegetable intake was not associated with risk of total cancer in this prospective cohort of women in Sweden.
Fruits and vegetables; Cancer; Cohort; Epidemiology
Although it is well known that multiple genes may influence prostate cancer risk, most current efforts at identifying prostate cancer risk variants rely on single-gene approaches. In previous work using mostly single-gene approaches, we observed significant associations (P < 0.05) for 6 of 46 polymorphisms in five genes in a Swedish prostate cancer case-control study population. We now report on the higher-order gene-gene interactions among those 46 genetic variants and the combined effect of the six polymorphisms with significant main effects for association with prostate cancer risk in 795 controls and 1,461 cases. Classification and regression tree analysis was used to evaluate higher-order gene-gene interactions. No interactions were confirmed by the result from logistic regressions. For the combined analysis, we tested the hypothesis that individuals carrying multiple copies of risk variants are at increased risk for prostate cancer. Individuals carrying more than eight copies of any risk variant were almost twofold more likely to get prostate cancer (OR = 1.99, P = 0.0014). A significant trend relationship was observed (P < 0.0001). In the present study, additive effects but not multiplicative effects among these six polymorphisms with significant main effects were observed.
interaction; prostate cancer; association; SNPs
Epidemiologic studies suggest positive associations between poor oral health and cardiovascular disease. The authors undertook a prospective study among 15,273 Swedish twins (1963–2000) to examine whether genetic factors underlying the 2 diseases could explain previous associations. They estimated hazard ratios and 95% confidence intervals controlling for individual factors and stratifying on twin pairs to control for familial effects. Quantitative genetic analyses estimated genetic correlations between oral diseases and cardiovascular disease outcomes. Tooth loss (hazard ratio (HR) = 1.2, 95% confidence interval (CI): 1.1, 1.4) and periodontal disease (HR = 1.3, 95% CI: 1.0, 1.4) were associated with small excess risks of cardiovascular disease; periodontal disease was also associated with coronary heart disease (HR = 1.4, 95% CI: 1.1, 1.6). Adjustment for genetic factors in co-twin analyses did not appreciably change estimates. In contrast, tooth loss was more strongly associated with coronary heart disease in twin models (HR = 2.1, 95% CI: 1.2, 3.8) compared with adjusting for individual factors alone (HR = 1.3, 95% CI: 1.1, 1.4). There was evidence of shared genetic factors between cardiovascular disease and tooth loss (rG = 0.18) and periodontal disease (rG = 0.29). Oral disease was associated with excess cardiovascular disease risk, independent of genetic factors. There appear to be common pathogenetic mechanisms between poor oral health and cardiovascular disease.
cardiovascular diseases; oral health; periodontal diseases; tooth loss; twin study
Acrylamide, a probable human carcinogen, is formed during the cooking of many commonly consumed foods. Data are scant on whether dietary acrylamide represents an important cancer risk in humans. We studied the association between acrylamide and prostate cancer risk using two measures of acrylamide exposure: intake from a food frequency questionnaire (FFQ) and acrylamide adducts to hemoglobin. We also studied the correlation between these two exposure measures. We used data from the population-based case-control study Cancer of the Prostate in Sweden (CAPS). Dietary data was available for 1499 cases and 1118 controls. Hemoglobin adducts of acrylamide were measured in blood samples from a subset of 170 cases and 161 controls. We calculated odds ratios (ORs) for the risk of prostate cancer in high versus low quantiles of acrylamide exposure using logistic regression. The correlation between FFQ acrylamide intake and acrylamide adducts in non-smokers was 0.25 (95% confidence interval: 0.14–0.35), adjusted for age, region, energy intake, and laboratory batch. Among controls the correlation was 0.35 (95% CI: 0.21–0.48); among cases it was 0.15 (95% CI: 0.00–0.30). The OR of prostate cancer for the highest versus lowest quartile of acrylamide adducts was 0.93 (95% CI: 0.47–1.85, p-value for trend=0.98). For FFQ acrylamide, the OR of prostate cancer for the highest versus lowest quintile was 0.97 (95% CI: 0.75–1.27, p trend=0.67). No significant associations were found between acrylamide exposure and risk of prostate cancer by stage, grade, or PSA level. Acrylamide adducts to hemoglobin and FFQ-measured acrylamide intake were moderately correlated. Neither measure of acrylamide exposure – hemoglobin adducts or FFQ – was associated with risk of prostate cancer.
acrylamide; diet; prostate cancer
Michelle Holmes and colleagues argue that there is an urgent need for longitudinal cohorts based in sub-Saharan Africa to address the growing burden of noncommunicable diseases in the region.
Selenium may affect prostate-cancer (PC) risk via its plasma carrier selenoprotein P which shows dramatically reduced expression in PC tumors and cell-lines. The selenoprotein P (SEPP1) Ala234 SNP allele is associated with lower plasma selenoprotein P in men, reducing the concentration/activity of other antioxidant selenoproteins. Selenium status also modifies the effect of mitochondrial superoxide dismutase (SOD2) SNP Ala16Val on PC risk. We investigated the relationship of these SNPs with PC risk. DNA from 2,975 cases and 1,896 age-matched controls from the population-based Prostate Cancer in Sweden (CAPS) study were genotyped using TaqMan® assays. Cases were designated aggressive (APC) or non-aggressive (NPC) at diagnosis by clinical criteria. Association with PC was investigated by logistic regression; gene-gene interaction using a general linear model. Mean plasma selenium measured in 169 controls was relatively-low (76.0±17.2μg/L). SNP genotype-distributions were in Hardy-Weinberg Equilibrium. SOD2-Ala16+ men were at greater PC risk (OR 1.19, 95%CI 1.03-1.37) compared to SOD2-Val16 homozygotes. Men homozygous for SEPP1-Ala234 who were also SOD2-Ala16+ had a higher risk of PC (OR 1.43, 95%CI 1.17-1.76) and APC (OR 1.60, 95%CI 1.22-2.09) than those who were SOD2-Val16 homozygotes (interaction, PC P=0.05, APC P=0.01). This interaction was stronger in ever-smokers: SOD2-Ala16+ men homozygous for SEPP1-Ala234 had an almost doubled risk of PC (OR 1.97, 95%CI 1.33-2.91; interaction P=0.001). In a low selenium population, SOD2-Ala16+ men homozygous for SEPP1-Ala234 are at increased risk of PC/APC especially if ever-smokers, because they are likely to produce more mitochondrial H2O2 that they cannot remove, thereby promoting prostate tumor-cell proliferation and migration.
mitochondrial superoxide dismutase; polymorphism; prostate cancer; selenium; selenoprotein P; SNPs