Epidemiology - identifying the causes and preventability of cancer?

Global cancer statistics, 2012

Cancer constitutes an enormous burden on society in more and less economically developed countries alike. The occurrence of cancer is increasing because of the growth and aging of the population, as well as an increasing prevalence of established risk factors such as smoking, overweight, physical inactivity, and changing reproductive patterns associated with urbanization and economic development. Based on GLOBOCAN estimates, about 14.1 million new cancer cases and 8.2 million deaths occurred in 2012 worldwide. Over the years, the burden has shifted to less developed countries, which currently account for about 57% of cases and 65% of cancer deaths worldwide. Lung cancer is the leading cause of cancer death among males in both more and less developed countries, and has surpassed breast cancer as the leading cause of cancer death among females in more developed countries; breast cancer remains the leading cause of cancer death among females in less developed countries. Other leading causes of cancer death in more developed countries include colorectal cancer among males and females and prostate cancer among males. In less developed countries, liver and stomach cancer among males and cervical cancer among females are also leading causes of cancer death. Although incidence rates for all cancers combined are nearly twice as high in more developed than in less developed countries in both males and females, mortality rates are only 8% to 15% higher in more developed countries. This disparity reflects regional differences in the mix of cancers, which is affected by risk factors and detection practices, and/or the availability of treatment. Risk factors associated with the leading causes of cancer death include tobacco use (lung, colorectal, stomach, and liver cancer), overweight/obesity and physical inactivity (breast and colorectal cancer), and infection (liver, stomach, and cervical cancer). A substantial portion of cancer cases and deaths could be prevented by broadly applying effective prevention measures, such as tobacco control, vaccination, and the use of early detection tests.

Comparison of male and female breast cancer incidence and mortality trends in Central Serbia

BACKGROUND

To compare breast cancer incidence and mortality trends in Central Serbia between males and females in the period 1999-2009.

MATERIALS AND METHODS

In this descriptive study, mortality data were obtained from the National Statistics Institute and morbidity data were derived from Institute of Public Health of Serbia for the period of interest.

RESULTS

Breast cancer is a leading cancer in the female population of Central Serbia, whereas in male population it is not on the list of 10 leading localizations, concerning both incidence as well as mortality. In the period 1999-2009 the average standardized incidence rates of breast cancer were 60.5/100,000 in women and 1.4/100,000 in men, while average standardized mortality rates were 20.4/100,000 and 0.4/100,000. The average standardized incidence and mortality rates were about 45 times higher in females than males. Male breast cancer comprises approximately 2.1% of all breast cancer cases. The average age-specific mortality and incidence rates increased with age in both sexes. In the observed period standardized mortality rates of breast cancer increased significantly only in men (y=0.320+0.021?, p=0.044).

CONCLUSIONS

The increase of breast cancer incidence in both sexes and mortality in men, indicate an urgent need for Serbian health professionals to apply existing cancer control and preventive measures. Male breast cancer is more present than in other world regions, with an outstanding increase of mortality, which demands a timely identification (screening) and adequate treatment. A national policy including mammography should be considered in the light of the newest findings.

Physical activity and cancer prevention: awareness and meeting the recommendations among adult Saudis

BACKGROUND

There is a scarcity of information about the proportion of the adult Saudi population that meet the recommended guidelines of physical activity (PA) to reduce cancer risk. Moreover, their awareness about the role of PA in cancer prevention is unclear.

OBJECTIVES

This cross-sectional study aimed at estimating the proportion of adult Saudis meeting the PA guidelines, specifically those recommended by American Cancer Society (ACS) for cancer prevention, and to assess the public awareness about the role of PA in cancer prevention.

MATERIALS AND METHODS

Using a multistage sampling method, 2,127 adult Saudis of both genders were recruited from 6 urban and 4 rural primary health care centers in Al Hassa, Saudi Arabia. Participants were personally interviewed to gather information about their sociodemographic characteristics, searching activity about PA and cancer, and the time spent in leisure time PA (moderate and vigorous)/week using the Global Physical Activity Questionnaire with show cards. Finally, items about the role of PA in cancer risk reduction were inquired.

RESULTS

Of the included participants, 11.6% met the recommendations for cancer prevention (≥ 45 minutes of moderate-vigorous PA activity/≥ 5 days/week or 225 minutes/week). Multivariate regression showed that being male (AOR=1.49, CI=1.09-2.06), <20 years of age (AOR=3.11, CI=2.03-4.76), and unemployed (AOR=2.22, CI=1.57-3.18) were significant predictors for meeting PA recommendations for cancer prevention. Only 11.4% of the sample indicated correctly the frequency and duration of PA required for an average adult to be physically active and while >70% of them indicated the role of PA in prevention of hypertension, coronary heart disease and lowering elevated blood cholesterol, only 18.6% and 21.7% correctly mentioned the role of PA in reducing colon and breast cancer risk, respectively. Poor knowledge was found among those with less than college education and aged ≥ 50 years. The level of knowledge was significantly positively correlated with total leisure time PA of the participants.

CONCLUSIONS

A minority of adult Saudis in Al Hassa was aware about the role of PA in cancer prevention and engaged in sufficient LTPA for cancer risk reduction benefits, highlighting the need for public health actions to include policies and programs that address factors deterring their participation in LTPA and increasing their awareness with remedies to manage the prevalent misconceptions.

Translational cancer research: balancing prevention and treatment to combat cancer globally

Cancer research is drawing on the human genome project to develop new molecular-targeted treatments. This is an exciting but insufficient response to the growing, global burden of cancer, particularly as the projected increase in new cases in the coming decades is increasingly falling on developing countries. The world is not able to treat its way out of the cancer problem. However, the mechanistic insights from basic science can be harnessed to better understand cancer causes and prevention, thus underpinning a complementary public health approach to cancer control. This manuscript focuses on how new knowledge about the molecular and cellular basis of cancer, and the associated high-throughput laboratory technologies for studying those pathways, can be applied to population-based epidemiological studies, particularly in the context of large prospective cohorts with associated biobanks to provide an evidence base for cancer prevention. This integrated approach should allow a more rapid and informed translation of the research into educational and policy interventions aimed at risk reduction across a population.

In vitro and in vivo anticancer effects of mevalonate pathway modulation on human cancer cells

Background:

The increasing usage of statins (the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) has revealed a number of unexpected beneficial effects, including a reduction in cancer risk.

Methods:

We investigated the direct anticancer effects of different statins approved for clinical use on human breast and brain cancer cells. We also explored the effects of statins on cancer cells using in silico simulations.

Results:

In vitro studies showed that cerivastatin, pitavastatin, and fluvastatin were the most potent anti-proliferative, autophagy inducing agents in human cancer cells including stem cell-like primary glioblastoma cell lines. Consistently, pitavastatin was more effective than fluvastatin in inhibiting U87 tumour growth in vivo. Intraperitoneal injection was much better than oral administration in delaying glioblastoma growth. Following statin treatment, tumour cells were rescued by adding mevalonate and geranylgeranyl pyrophosphate. Knockdown of geranylgeranyl pyrophosphate synthetase-1 also induced strong cell autophagy and cell death in vitro and reduced U87 tumour growth in vivo. These data demonstrate that statins main effect is via targeting the mevalonate synthesis pathway in tumour cells.

Conclusions:

Our study demonstrates the potent anticancer effects of statins. These safe and well-tolerated drugs need to be further investigated as cancer chemotherapeutics in comprehensive clinical studies.

Mechanisms by Which Pleiotropic Amphiphilic n-3 PUFA Reduce Colon Cancer Risk

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. Genetic susceptibility and diet are primary determinants of cancer risk and tumor behavior. Experimental, epidemiological, and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing chronic inflammation and colon cancer. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely alters membrane structure/ cytoskeletal function, impacting membrane receptor function and downstream signaling cascades, including gene expression profiles and cell phenotype. In addition, n-3 PUFA can synergize with other potential anti-tumor agents, such as fermentable fiber and curcumin. With the rising prevalence of diet-induced obesity, there is also an urgent need to elucidate the link between chronic inflammation in adipose tissue and colon cancer risk in obesity. In this review, we will summarize recent developments linking n-3 PUFA intake, membrane alterations, epigenetic modulation, and effects on obesity-associated colon cancer risk.

Priorities for the primary prevention of breast cancer

Despite recent calls to intensify the search for new risk factors for breast cancer, acting on information that we already have could prevent thousands of cases each year. This article reviews breast cancer primary prevention strategies that are applicable to all women, discusses the underutilization of chemoprevention in high-risk women, highlights the additional advances that could be made by including young women in prevention efforts, and comments on how the molecular heterogeneity of breast cancer affects prevention research and strategies.

Dinner-to-bed time and post-dinner walk: new potential independent factors in esophageal cancer development

PURPOSE

Esophageal squamous cell carcinoma (ESCC) remains a significant cause of morbidity and mortality worldwide. The aim of the study was to investigate the effects of shorter dinner-to-bed time and post-dinner walk on ESCC risk.

METHODS

A matched case-control study with 232 ESCC patients and 286 age- and gender-matched healthy controls enrolled was conducted. Conditional logistic regression was used to calculated odds ratio (OR) and 95 % confidence intervals (95 % CI).

RESULTS

The adjusted ORs of ESCC for subjects with shorter dinner-to-bed time (<3 h) were 2.84 (95 % CI 1.64-4.29), relative to those with longer dinner-to-bed time (≥4 h). While post-dinner walk was associated with a decreased ESCC risk (adjusted OR 0.64; 95 % CI 0.41-0.89). What's more, when reflux symptom was added into the multivariate models, risk estimate for shorter dinner-to-bed time still remained statistically significant (p = 0.003), and risk estimate for post-dinner walk changed slightly. In the subgroup analysis stratified by post-dinner walk, subjects with shorter dinner-to-bed time experienced similar risk (adjusted ORs 2.71 vs. 2.82).

CONCLUSIONS

Shorter dinner-to-bed time is a potential risk factor for ESCC and post-dinner walk is a protective factor, providing evidence for the effect of lifestyle factors on ESCC risk.

Disparities in female breast cancer mortality rates between urban centers and rural areas of Brazil: ecological time-series study

OBJECTIVES

To evaluate trends in breast cancer mortality in urban centers and rural areas of Brazil.

METHODS

Ecological time-series study using data on breast cancer deaths and census. Mortality trends were analyzed using change-point regression: 1980-2010.

RESULTS

A declining trend was found in five urban centers: São Paulo (APC = -1.7%), Porto Alegre (APC = -1.6%), Belo Horizonte (APC = -1.2%), Rio de Janeiro and Recife (APC = -0.9%). An increasing was found in: Porto Velho (APC = 9.0%), Teresina (APC = 4.6%), João Pessoa (APC = 1.6%), Belém (APC = 0.8%) and Fortaleza (APC = 0.5%). In the majority of rural areas, mortality continues to rise, with the exception of some areas in the southern.

CONCLUSION

Disparities in breast cancer mortality were found across the country, with increasing trends occurring predominantly in the north and northeastern regions. One of the reasons for this disparity may be that access to treatment is more difficult for patients living in rural areas and in the north of Brazil.

The microbiome and cancer

Microbiota and host form a complex 'super-organism' in which symbiotic relationships confer benefits to the host in many key aspects of life. However, defects in the regulatory circuits of the host that control bacterial sensing and homeostasis, or alterations of the microbiome, through environmental changes (infection, diet or lifestyle), may disturb this symbiotic relationship and promote disease. Increasing evidence indicates a key role for the bacterial microbiota in carcinogenesis. In this Opinion article, we discuss links between the bacterial microbiota and cancer, with a particular focus on immune responses, dysbiosis, genotoxicity, metabolism and strategies to target the microbiome for cancer prevention.

Biofunctional quantum dots as fluorescence probe for cell-specific targeting

We describe here the synthesis, characterization, bioconjugation, and application of water-soluble thioglycolic acid TGA-capped CdTe/CdS quantum dots (TGA-QDs) for targeted cellular imaging. Anti-human epidermal growth factor receptor 2 (HER2) antibodies were conjugated to TGA-QDs to target HER2-overexpressing cancer cells. TGA-QDs and TGA-QDs/anti-HER2 bioconjugates were characterized by fluorescence and UV-Vis spectroscopy, X-ray diffraction (XRD), hydrodynamic sizing, electron microscopy, and gel electrophoresis. TGA-QDs and TGA-QDs/anti-HER2 were incubated with cells to examine cytotoxicity, targeting efficiency, and cellular localization. The cytotoxicity of particles was measured using an MTT assay and the no observable adverse effect concentration (NOAEC), 50% inhibitory concentration (IC50), and total lethal concentration (TLC) were calculated. To evaluate localization and targeting efficiency of TGA-QDs with or without antibodies, fluorescence microscopy and flow cytometry were performed. Our results indicate that antibody-conjugated TGA-QDs are well-suited for targeted cellular imaging studies.

Dicopper(II) and dizinc(II) complexes with nonsymmetric dinucleating ligands based on indolo[3,2-c]quinolines: synthesis, structure, cytotoxicity, and intracellular distribution

Dicopper(II) and dizinc(II) complexes [Cu2((MeOOC)L(COO))(CH3COO)2] (1) and [Zn2((MeOOC)L(COO))(CH3COO)2] (2) were synthesized by reaction of Cu(CH3COO)2·H2O and Zn(CH3COO)2·2H2O with a new nonsymmetric dinucleating ligand (EtOOC)HL(COOEt) prepared by condensation of 6-hydrazinyl-11H-indolo[3,2-c]quinoline with diethyl-2,2'-((3-formyl-2-hydroxy-5-methylbenzyl)azanediyl)diacetate. The design and synthesis of this elaborate ligand was performed with the aim of increasing the aqueous solubility of indolo[3,2-c]quinolines, known as biologically active compounds, and investigating the antiproliferative activity in human cancer cell lines and the cellular distribution by exploring the intrinsic fluorescence of the indoloquinoline scaffold. The compounds have been comprehensively characterized by elemental analysis, spectroscopic methods (IR, UV-vis, (1)H and (13)C NMR spectroscopy), ESI mass spectrometry, magnetic susceptibility measurements, and UV-vis complex formation studies (for 1) as well as by X-ray crystallography (1 and 2). The antiproliferative activity of (EtOOC)HL(COOEt), 1, and 2 was determined by the MTT assay in three human cancer cell lines, namely, A549 (nonsmall cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon adenocarcinoma), yielding IC50 values in the micromolar concentration range and showing dependence on the cell line. The effect of metal coordination on cytotoxicity of (EtOOC)HL(COOEt) is also discussed. The subcellular distribution of (EtOOC)HL(COOEt) and 2 was investigated by fluorescence microscopy, revealing similar localization for both compounds in cytoplasmic structures.

Poor self-rated health associated with an increased risk of subsequent development of lung cancer

PURPOSE

Self-rated health has shown to be a strong predictor of mortality and some major chronic diseases. The purpose of this study was to investigate whether poor self-rated health also was related to an increased risk of subsequent development of cancer.

METHODS

Information on self-rated health, life-style factors, and other health-related risk factors was ascertained in a cohort of 25,532 persons participating in the Hordaland Health Study in 1997-1999. Information on development of cancer during 10 years of follow-up was obtained from the Norwegian Cancer Registry. The relationship between self-rated health and development of cancer was examined using Cox regression analysis adjusting for smoking and other life-style factors.

RESULTS

Respondents reporting a poor health showed a non-significant increased risk of overall cancer. Sub-analysis of the four most common types of cancer showed a statistically significant association between self-rated health and lung cancer. The adjusted hazard ratio was 3.88 (95% CI; 0.99, 15.8) for those rating their health as poor compared to very good (p for trend = 0.038). For the other types of cancer, we found a non-significant elevated risk associated with poor self-rated health.

CONCLUSION

Respondents who perceive their health as poor had an increased risk of developing lung cancer also after adjusting for smoking. This suggests that self-rated health reflects a broad range of factors important for development of this cancer type. Nevertheless, due to the explorative analysis of the specific cancer types, these findings need to be repeated before elaborate interpretations can be made.

Characteristics of fatty acid distribution is associated with colorectal cancer prognosis

To investigate tissue fatty acid distribution in relation to the incidence of colorectal cancer prognosis, adjacent normal tissue and cancerous tissue from 35 samples of clinically incident colorectal cancer were obtained. Fatty acids were measured in the colorectal mucosa phospholipid fraction by gas chromatography mass spectrometry. Palmitoleic acid and oleic acid were significantly lower in colorectal cancerous tissue, ranging from 20% to 50% less than the adjacent normal tissue. The omega-6 (n-6) fatty acid family members (20:2, 20:3, 20:4 and 22:4) were higher by 1-3 fold in cancerous colorectal tissue. Contrary with the high level of n-6 fatty acids, about a 37% to 87% reduction in EPA and DHA was observed in colorectal cancerous tissue. A higher level of linoleic acid and arachidonic acid was detected in the C cancer stage than in the B cancer stage (p<0.05), but a lower level of oleic acid and docosahexenoic acid was detected in the C cancer stage (p<0.05). The fatty acid distribution of colorectal tissue is strongly linked to the incidence of colorectal cancer. This study also provides scientific basis for identifying novel biomarkers for the diagnosis and treatment of cancer.

Cancer prevention for the next generation

Given the continued growth in the number of persons with cancer in the United States, the primary prevention of cancer remains an urgent public health priority. As the field of cancer prevention continues to mature and scientific knowledge evolves, it is imperative to challenge the status quo and embrace new approaches to cancer prevention. In this commentary, we summarize recent trends and some of the scientific advances that have been made over the past few decades regarding the complex process of cancer development and the interaction of individual and social risk factors. We examine some of the assumptions and terminology that have characterized cancer prevention approaches for more than a quarter century and the impact of these assumptions and our use of terminology. We propose that it is possible for today's youth to experience lower cancer incidence rates as adults compared with previous generations. To accomplish this goal, a more transdisciplinary and multifaceted approach is needed, adapted as appropriate for different populations and stages of life. The greatest improvements in cancer prevention may occur as a result of innovative, multilevel interventions that build on the expanding scientific evidence base.

Genetic variant rs7758229 in 6q26-q27 is not associated with colorectal cancer risk in a Chinese population

BACKGROUND

A recent genome-wide association study has identified a new genetic variant rs7758229 in SLC22A3 for colorectal cancer susceptibility in a Japanese population, but it is unknown whether this newly identified variant is associated with colorectal cancer in other populations, including the Chinese population.

METHODS

We examined the associations between rs7758229 and colorectal cancer risk among 1,147 cases and 1,203 controls matched by age and sex. Logistic regression model was used to assess the associations.

RESULTS

No significant association was found between rs7758229 and colorectal cancer risk (OR = 0.95, 95%CI = 0.84-1.09, P = 0.463). Similar results were observed in the stratification of tumor location (OR = 0.94, 95%CI = 0.80-1.11, P = 0.481 for colon cancer, and OR = 0.96, 95%CI = 0.82-1.13, P = 0.621 for rectum cancer).

CONCLUSIONS

Our findings did not support an association between rs7758229 in 6q26-q27 and the risk of colorectal cancer in a Chinese population.

Information seeking from media and family/friends increases the likelihood of engaging in healthy lifestyle behaviors

The amount of cancer-related information available to the general population continues to grow; yet, its effects are unclear. This study extends previous cross-sectional research establishing that cancer information seeking across a variety of sources is extensive and positively associated with engaging in health-related behaviors. The authors studied how active information seeking about cancer prevention influenced three healthy lifestyle behaviors using a 2-round nationally representative sample of adults ages 40-70 years (n = 1,795), using propensity scoring to control for potential confounders including baseline behavior. The adjusted odds of dieting at follow-up were 1.51 (95% CI: 1.05, 2.19) times higher for those who reported baseline seeking from media and interpersonal sources relative to nonseekers. Baseline seekers ate 0.59 (95% CI: 0.28, 0.91) more fruits and vegetable servings per day and exercised 0.36 (95% CI: 0.12, 0.60) more days per week at 1-year follow-up compared with nonseekers. The effects of seeking from media and friends/family on eating fruits and vegetables and exercising were independent of seeking from physicians. The authors offer several explanations for why information seeking predicts healthy lifestyle behaviors: information obtained motivates these behaviors; information sought teaches specific techniques; and the act of information seeking may reinforce a psychological commitment to dieting, eating fruits and vegetables, and exercising.

Evaluation of a new approach to the treatment of lymphedema resulting from breast cancer therapy

PURPOSE

The aim of this study was to evaluate a new form of intensive treatment for arm lymphedema.

METHODS

A prospective study of 66 patients with breast cancer-related lymphedema was performed. The ages of the patients ranged from 35 to 83 years old with a mean of 58.8 years. Diagnosis of lymphedema was made by physical examination and water-displacement volumetry (a difference of ≥ 200 mL between arms). All the patients were submitted to clinical treatment in an outpatient setting which involved a once-weekly session of 3 to 4h of manual and mechanical lymph drainage, myolymphokinetic activities and exercising using facilitating apparatuses and the use of a medical compression sleeve. Monthly volumetry evaluations were routinely performed. The Student t-test was employed for statistical analysis with an alpha level of 5% (p<0.05) being considered significant.

RESULTS

The mean follow-up time between cancer treatment and this study was 12.3 months. A significant reduction in the size of the arms was observed for all patients. The mean difference between the lymphedematous and normal arms of all patients was 553.8 mL at the start of treatment and a mean reduction of 70.1% (388.7 mL) of the edema was achieved (p=0.0001).

CONCLUSION

In our experience, this model of treatment appeared efficacious in decreasing and maintaining the reduction in volume of arm in breast cancer-related lymphedema.

Age Interactions in Breast Cancer: An Analysis of a 10-Year Multicentre Study in China

OBJECTIVES: The effects of age at diagnosis on the clinical characteristics of breast cancer and trends over time were investigated in Chinese women. METHODS: Data from 4211 women with pathologically confirmed primary breast cancer collected between 1999 and 2008 for a multicentre retrospective study were analysed according to age at diagnosis. RESULTS: Age at diagnosis ranged from 21 to 86 years, with a mean of 48.7 years, and was shown to be significantly related to tumour size, lymph node status, hormone receptor status and human growth factor receptor-2 status, but not to pathological type or tumour, node, metastasis stage. The age-corrected proportion of patients aged 50 – 64 years at diagnosis increased significantly between 1999 and 2008. There was a significant difference in the age-corrected distribution of age at diagnosis in China compared with Western countries. CONCLUSIONS: Age at diagnosis is related to the clinical and pathological characteristics of breast cancer. The age at diagnosis in China increased over the decade from 1999 to 2008, but is still lower than in Western countries.

The combination of depressive symptoms and smoking shorten life expectancy among the aged

BACKGROUND

Depression is a potential risk factor for mortality among the aged and it is also associated with other chronic diseases and unhealthy lifestyles that may also affect mortality. The purpose of this study was to investigate the association between depressive symptoms and mortality, controlling for health, nutritional status, and life-style factors.

METHODS

A cohort of elderly people (N = 167) was followed-up for ten years. Information on socio-demographic characteristics, medical history, smoking, and alcohol consumption was collected. The primary outcome was all-cause mortality; the secondary outcome was cancer-specific mortality. The Geriatric Depression Scale (GDS-15) was used to assess depression. Using a multivariable Cox proportional hazards regression, we examined the association between depressive symptoms and mortality.

RESULTS

Elderly people with depression (scoring above the depression cut-off of 7) had a 53% increased risk of mortality (relative risk (RR) 1.53; 95%CI: 1.05-2.24) compared to non-depressed subjects. The combination of depressive symptoms with smoking was associated with a particularly higher risk of mortality (RR: 2.61; 95%CI: 1.28-5.31), after controlling for potential confounders.

CONCLUSIONS

Depressive symptoms are associated with a significantly increased risk of all-cause mortality. The combination of depressive symptoms and smoking shorten life expectancy among the aged.

Preventability of cancer: the relative contributions of biologic and social and physical environmental determinants of cancer mortality

Whereas models of cancer disparities and variation in cancer burden within population groups now specify multiple levels of action from biologic processes to individual risk factors and social and physical contextual factors, approaches to estimating the preventable proportion of cancer use more traditional direct models often from single exposures to cancer at specific organ sites. These approaches are reviewed, and the strengths and limitations are presented. The need for additional multilevel data and approaches to estimation of preventability are identified. International or regional variation in cancer may offer the most integrated exposure assessment over the life course. For the four leading cancers, which account for 50% of incidence and mortality, biologic, social, and physical environments play differing roles in etiology and potential prevention. Better understanding of the interactions and contributions across these levels will help refine prevention strategies.

Commentary: eight ways to prevent cancer: a framework for effective prevention messages for the public

Research over the past 40 years has convincingly shown that lifestyle factors play a huge role in cancer incidence and mortality. The public, though, can often discount the preventability of cancer. That health information on the Internet is a vast and often scientifically suspect commodity makes promoting important and sound cancer prevention messages to the public even more difficult. To help address these issues and improve the public's knowledge of, and attitudes toward, cancer prevention, there need to be concerted efforts to create evidence-based, user-friendly information about behaviors that could greatly reduce overall cancer risk. Toward this end, we condensed the current scientific evidence on the topic into eight key behaviors. While not an end in themselves, "Eight Ways to Stay Healthy and Prevent Cancer" forms an evidence-based and targeted framework that supports broader cancer prevention efforts.

A prospective association between quality of life and risk for cancer

AIM

The contributions of social and especially of psychological factors to cancer development have been questioned. The goal of this study was to investigate, in a longitudinal setting, the prospective associations between self-reported measures of social relations, subjective health (physical and mental) and quality of life and the risk for cancer.

METHODS

In 1993, 4493 people in the Copenhagen Perinatal Cohort were asked to rate their social relations, their physical and mental health and their quality of life. The study population was followed until the end of 2006 for registration of cancer in the Danish Hospital Discharge Register.

RESULTS

During the follow-up period, cancer was diagnosed in 102 people. When compared with people with very good quality of life, those who rated their quality of life as poor had a hazard ratio of 1.90 (95% confidence interval [CI], 1.1-3.4) for cancer, and those who rated their quality of life as good had a hazard ratio of 1.31 (95% CI, 0.8-2.2), after adjustment for age, sex, income, lifestyle factors and number of health problems. Self-rated physical and mental health were significantly associated with the risk for cancer, but the estimates became non-significant after adjustment for confounding factors. Social relations were not associated with the risk for cancer.

CONCLUSION

Broad assessment of general well-being, self-rated as global quality of life, appears to be a better predictor of cancer risk than more specific information on social relations and health.

What factors do cancer patients believe contribute to the development of their cancer? (New South Wales, Australia)

OBJECTIVE

To analyze Australian cancer patients' beliefs about factors contributing to the development of their cancer.

METHODS

As part of a case-control study (The Cancer Council NSW Cancer, Lifestyle and Evaluation of Risk Study), a total of 2,857 cancer patients (open to all types of cancer) were surveyed and via an open-ended question, were asked to specify factors they think contributed to the development of their cancer. Qualitative analysis and categorical techniques were used to analyze the data.

RESULTS

About half, 53%, of patients specified at least one contributing factor. The odds of a person specifying a contributing factor increased with time period since diagnosis (p = 0.0006). Patients most frequently specified, respectively: "Stress" (15.4%), "Genetics/hereditary" (10.9%) and "Smoking" (6.2%). Among factors specified the largest proportion (24.1%) was perceived to be "Non-modifiable."

CONCLUSION

Cancer patients specified a broad range of factors and agents to which their disease may be attributed. Some of these were poorly correlated with epidemiological rankings of attributable risk factors. The role of psychosocial and genetic factors was overstated. Misconceptions regarding the causes of cancer are a key consideration of health professionals when devising communication strategies around cancer prevention.

Low Social Status Markers: Do They Predict Depressive Symptoms in Adolescence?

Some markers of social disadvantage are associated robustly with depressive symptoms among adolescents: female gender and lower socioeconomic status (SES), respectively. Others are associated equivocally, notably Black v. White race/ethnicity. Few studies examine whether markers of social disadvantage by gender, SES, and race/ethnicity jointly predict self-reported depressive symptoms during adolescence; this was our goal. Secondary analyses were conducted on data from a socioeconomically diverse community-based cohort study of non-Hispanic Black and White adolescents (N = 1,263, 50.4% female). Multivariable general linear models tested if female gender, Black race/ethnicity, and lower SES (assessed by parent education and household income), and their interactions predicted greater depressive symptoms reported on the Center for Epidemiological Studies-Depression scale. Models adjusted for age and pubertal status. Univariate analyses revealed more depressive symptoms in females, Blacks, and participants with lower SES. Multivariable models showed females across both racial/ethnic groups reported greater depressive symptoms; Blacks demonstrated more depressive symptoms than did Whites but when SES was included this association disappeared. Exploratory analyses suggested Blacks gained less mental health benefit from increased SES. However there were no statistically significant interactions among gender, race/ethnicity, or SES. Taken together, we conclude that complex patterning among low social status domains within gender, race/ethnicity, and SES predicts depressive symptoms among adolescents.

Functional variants of -1318T > G and -673C > T in c-Jun promoter region associated with increased colorectal cancer risk by elevating promoter activity

C-Jun plays important roles in the development of multiple cancers, but no well-designed association studies have been conducted to assess the roles of its genetic polymorphisms in cancer risk. In a cohort of 1016 pairs of colorectal cancer (CRC) patients and matched cancer-free controls, we investigated two genetic polymorphisms in the promoter regions of the c-Jun (rs4646999, -673C > T and rs2760501, -1318T > G) via the Taqman assay and evaluated the association between two polymorphisms and risk of CRC. We found that both the -1318G and -673C variant genotypes were associated with an increased risk of CRC [-1318TG: odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.04-1.54; -1318GG: OR = 1.63, 95% CI = 1.03-2.60; -673CT: OR = 1.60, 95% CI = 1.23-2.07; -673CC: OR = 1.80, 95% CI = 1.36-2.37]. Haplotype association analysis showed that compared with the carriers of -1318T-673T haplotype, carriers of the -1318T-673C, -1318G-673T, and -1318G-673C haplotypes all had a significantly increased risk of CRC (P < 0.05 for all). The combined genotypes incorporating both polymorphisms obtained a more significantly additive risk of CRC (one variant genotype: OR = 1.81, 95% CI = 1.30-2.51; two variant genotype: OR = 2.42, 95% CI = 1.70-3.44). Moreover, we found that the change of the -1318T to G allele interact with the -673T to C allele elevated the transcription activity of the c-Jun, and we confirmed the same trends by analyzing c-Jun protein expression in the CRC tissues from patients carrying different number of variant genotypes. This study suggests that -673C > T and -1318T > G genetic variants in c-Jun promoter regions contribute to an increased risk of CRC, possibly by elevating the transcription activity and protein expression levels that appeared to upregulate activity of c-Jun thus tumorigenesis.

Global cancer statistics

The global burden of cancer continues to increase largely because of the aging and growth of the world population alongside an increasing adoption of cancer-causing behaviors, particularly smoking, in economically developing countries. Based on the GLOBOCAN 2008 estimates, about 12.7 million cancer cases and 7.6 million cancer deaths are estimated to have occurred in 2008; of these, 56% of the cases and 64% of the deaths occurred in the economically developing world. Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among females, accounting for 23% of the total cancer cases and 14% of the cancer deaths. Lung cancer is the leading cancer site in males, comprising 17% of the total new cancer cases and 23% of the total cancer deaths. Breast cancer is now also the leading cause of cancer death among females in economically developing countries, a shift from the previous decade during which the most common cause of cancer death was cervical cancer. Further, the mortality burden for lung cancer among females in developing countries is as high as the burden for cervical cancer, with each accounting for 11% of the total female cancer deaths. Although overall cancer incidence rates in the developing world are half those seen in the developed world in both sexes, the overall cancer mortality rates are generally similar. Cancer survival tends to be poorer in developing countries, most likely because of a combination of a late stage at diagnosis and limited access to timely and standard treatment. A substantial proportion of the worldwide burden of cancer could be prevented through the application of existing cancer control knowledge and by implementing programs for tobacco control, vaccination (for liver and cervical cancers), and early detection and treatment, as well as public health campaigns promoting physical activity and a healthier dietary intake. Clinicians, public health professionals, and policy makers can play an active role in accelerating the application of such interventions globally.

The ovarian dysgenesis syndrome

New thinking has arisen about the origin of adult onset diseases stemming from a collective body of evidence commonly referred to as the developmental origins of health and disease. This conceptual paradigm posits that certain adult onset diseases arise during critical or sensitive windows of human development or even transgenerationally. The testicular dysgenesis hypothesis (TDS) postulates an in utero origin for adverse male reproductive outcomes, and is an excellent example of the early origins of the paradigm. Despite similarities in the development of the male and female reproductive tracks, noticeably absent is a collective body of evidence focusing on the plausibility of an early origin for gynecologic outcomes and later onset of adult diseases. Using the TDS paradigm, we synthesized the available literature relative to the ovarian dysgenesis syndrome (ODS), which we define as alterations in ovarian structure or function that may manifest as fecundity impairments, gynecologic disorders, gravid diseases or later onset adult diseases. We evaluated environmental exposures, particularly the role of endocrine disrupting chemicals, in relation to these outcomes, and found evidence (although fragmented) consistent with an in utero origin of gynecologic outcomes, which in turn is associated with later onset of adult diseases. The findings are interpreted within the ODS paradigm while delineating methodological challenges and future research opportunities designed to answer critical data gaps regarding the origin of fecundity, gravid health and chronic diseases affecting the female population.

Polymorphisms of tumor necrosis factor-alpha and breast cancer risk: a meta-analysis

We conducted a meta-analysis to assess the association between tumor necrosis factor-alpha (TNF-alpha) gene TNFA -308 (G>A), TNFA -238 (G>A), TNFA -857 (C>T), TNFA -863 (C>A), TNFA -1031 (T>C), TNFA -1210 (A>T) polymorphisms and breast cancer(BC) susceptibility. We also performed subgroup analyses based on ethnicity (Caucasian, Asian, and African). An extensive search was performed to identify all case-control studies investigating such association. Thirteen eligible studies, including 10,236 BC patients and 13,143 controls, were identified. No significant association was observed in all genotypes in worldwide populations, but stratification by ethnicity indicated that the TNFA -308 A allele was associated with a decreased risk of BC compared with the G allele in Caucasian individuals (OR = 0.927, 95%CI = 0.879-0.978). Similar results were obtained when the A/A +A/G genotype was compared with the G/G genotype. In addition, meta-analysis results indicated that the A/A genotype of TNFA -308 was a risk factor for BC in African (A/A vs. G/G OR = 4.085 95%CI = 1.460-11.425; A/A vs. G/A OR = 4.861 95%CI = 1.746-13.527; A/A vs. G/A + G/G OR = 4.246 95%CI = 1.551-11.625), but not in Caucasian or Asian individuals. In conclusion, the results of this meta-analysis indicate that the TNFA -308 A allele may be an important protective factor for BC in European individuals, but it is not likely to confer susceptibility to BC in worldwide populations. In addition, the AA genotype of TNFA -308 may be a risk factor for BC in African individuals. Besides, other polymorphisms were not associated with BC susceptibility.

Folic acid-CdTe quantum dot conjugates and their applications for cancer cell targeting

In this study, we report the preparation, luminescence, and targeting properties of folic acid-CdTe quantum dot conjugates. Water-soluble CdTe quantum dots were synthesized and conjugated with folic acid using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-N-hydroxysuccinimide chemistry. The influence of folic acid on the luminescence properties of CdTe quantum dots was investigated, and no energy transfer between them was observed. To investigate the efficiency of folic acid-CdTe nanoconjugates for tumor targeting, pure CdTe quantum dots and folic acid-coated CdTe quantum dots were incubated with human nasopharyngeal epidermal carcinoma cell line with positive expressing folic acid receptors (KB cells) and lung cancer cells without expression of folic acid receptors (A549 cells). For the cancer cells with positive folate receptors (KB cells), the uptake for CdTe quantum dots is very low, but for folic acid-CdTe nanoconjugates, the uptake is very high. For the lung cancer cells without folate receptors (A549 cells), the uptake for folic acid-CdTe nanoconjugates is also very low. The results indicate that folic acid is an effective targeting molecule for tumor cells with overexpressed folate receptors.

Global patterns of cancer incidence and mortality rates and trends

While incidence and mortality rates for most cancers (including lung, colorectum, female breast, and prostate) are decreasing in the United States and many other western countries, they are increasing in several less developed and economically transitioning countries because of adoption of unhealthy western lifestyles such as smoking and physical inactivity and consumption of calorie-dense food. Indeed, the rates for lung and colon cancers in a few of these countries have already surpassed those in the United States and other western countries. Most developing countries also continue to be disproportionately affected by cancers related to infectious agents, such as cervix, liver, and stomach cancers. The proportion of new cancer cases diagnosed in less developed countries is projected to increase from about 56% of the world total in 2008 to more than 60% in 2030 because of the increasing trends in cancer rates and expected increases in life expectancy and growth of the population. In this review, we describe these changing global incidence and mortality patterns for select common cancers and the opportunities for cancer prevention in developing countries.

Prevention trials: their place in how we understand the value of prevention strategies

Several key factors bear on the interpretation of prevention trials and observational studies that inform prevention strategies. These factors include the underlying disease process and aspects of the intervention: sustainability of behavior change, the time course of the intervention within the disease process, dose and duration of exposure needed to effect risk reduction, durability of the impact of intervention, and methodological problems in implementing and interpreting randomized trials and observational studies to evaluate prevention strategies. The question asked through an intent-to-treat analysis of a randomized controlled trial (RCT) differs from that in the observational setting. Furthermore, the long duration necessary to conduct prevention trials and the resulting lack of adherence to therapy can bias results toward the null. A broader range of approaches to evaluate prevention interventions and programs with improved knowledge synthesis and translation to public health practice will speed our progress toward achieving public health and prevention of chronic diseases.

Modifier-concept of colorectal carcinogenesis: Lipidomics as a technical tool in pathway analysis

In the modifier concept of intestinal carcinogenesis, lipids have been established as important variables and one focus is given to long-chain fatty acids. Increased consumption of long-chain fatty acids is in discussion to modify the development of colorectal carcinoma in humans. Saturated long-chain fatty acids, in particular, are assumed to promote carcinogenesis, whereas polyunsaturated forms are likely to act in the opposite way. At present, the molecular mechanisms behind these effects are not well understood. Recently, it has been demonstrated by lipidomics and associated molecular techniques, that activation and metabolic channeling of long-chain fatty acids are important mechanisms to modify colorectal carcinogenesis. In this Editorial, an overview about the present concept of long-chain fatty acids and its derivatives in colorectal carcinogenesis as well as technical algorithms in lipid analysis is given.

Cancer prevention in the developing world: mission impossible?

Cancer is set to become the newest epidemic in the developing world. This fact is still largely unknown. The UICC, therefore, has been acting in order to inform policymakers, with the aim of pushing them to act in order to tackle this looming disaster. The implementation of a cancer control plan, encompassing prevention, screening and treatment in each country, should therefore become the declared goal of all health policymakers worldwide.

Environmental exposure measurement in cancer epidemiology

Environmental exposures, used in the broadest sense of lifestyle, infections, radiation, natural and man-made chemicals and occupation, are a major cause of human cancer. However, the precise contribution of specific risk factors and their interaction, both with each other and with genotype, continues to be difficult to elucidate. This is partially due to limitations in accurately measuring exposure with the subsequent risk of misclassification. One of the primary challenges of molecular cancer epidemiology therefore is to improve exposure assessment. Progress has been made with biomarkers such as carcinogens and their metabolites, DNA and protein adducts and mutations measured in various tissues and body fluids. Nevertheless, much remains to be accomplished in order to establish aetiology and provide the evidence base for public health decisions. This review considers some of the principles behind the application of exposure biomarkers in cancer epidemiology. It also demonstrates how the same biomarkers can contribute both to establishing the biological plausibility of associations between exposure and disease and be valuable endpoints in intervention studies. The potential of new technologies such as transcriptomics, proteomics and metabonomics to provide a step change in environmental exposure assessment is discussed. An increasing recognition of the role of epigenetic changes in carcinogenesis presents a fresh challenge as alterations in DNA methylation, histone modification and microRNA in response to environmental exposures demand a new generation of exposure biomarker. The overall importance of this area of research is brought into sharp relief by the large prospective cohort studies (e.g. UK Biobank) which need accurate exposure measurement in order to shed light on the complex gene:environment interactions underlying common chronic disorders including cancer. It is suggested that a concerted effort is now required, with appropriate funding, to develop and validate the required exposure assessment methodology before these cohorts come to maturity.

Psychological distress and cancer mortality

BACKGROUND

Psychological distress, such as ongoing depression and anxiety-related symptomatology, has been associated with a higher risk of incident cancer and poorer survival, although previous studies have not compared prognostic and etiological effects within the same sample. We examined the association between psychological distress and cancer mortality in a sample comprising participants with and without previous cancer admissions.

METHODS

Data were collected from a community-based sample of 15,453 men and women (including 295 people with cancer history) and prospectively linked to a patient-based database of cancer registry and deaths during an average follow-up of 7.0+/-3.3 years. Psychological distress was assessed using the 12-item version of the General Health Questionnaire (GHQ-12).

RESULTS

There were 425 incident cancer deaths. Psychological distress (GHQ-12 > or =4) was associated with increased cancer mortality in participants with cancer history [age, gender, social status, marital status, body mass index, smoking, alcohol, and physical activity; adjusted hazard ratio (HR)=1.97; 95% confidence interval (95% CI)=1.05-3.71; P=.035], but not in participants without cancer history. Among participants without cancer history, there was, however, an association between distress and lung cancer death (age- and gender-adjusted HR=2.04; 95% CI=1.36-3.06; P=.001), although adjustment for covariates attenuated this association.

CONCLUSIONS

Psychological distress was a predictor of cancer mortality, especially in lung cancer. The presence of participants with cancer history in community-based cohorts may overestimate the association between psychological distress and subsequent cancer mortality.

On the impact of the molecule structure in chemical carcinogenesis

Cancer is as a highly complex and multifactorial disease responsible for the death of hundreds of thousands of people in the western countries every year. Since cancer is clonal and due to changes at the level of the genetic material, viruses, chemical mutagens and other exogenous factors such as short-waved electromagnetic radiation that alter the structure of DNA are among the principal causes. The focus of this present review lies on the influence of the molecular structure of two well-investigated chemical carcinogens from the group of polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP). Although there is only one additional benzo ring present in the latter compound, DBP exerts much stronger genotoxic and carcinogenic effects in certain tumor models as compared to BP. Actually, DBP has been identified as the most potent tumorigen among all carcinogenic PAHs tested to date. The genotoxic effects of both compounds investigated in mammalian cells in culture or in animal models are described. Comparison of enzymatic activation, DNA binding levels of reactive diol-epoxide metabolites, efficiency of DNA adduct repair and mutagenicity provides some clues on why this compound is about 100-fold more potent in inducing tumors than BP. The data published during the past 20 years support and strengthen the idea that compound-inherent physicochemical parameters, along with inefficient repair of certain kinds of DNA lesions formed upon metabolic activation, can be considered as strong determinants for high carcinogenic potency of a chemical.

Psychologic predictors of cancer information avoidance among older adults: the role of cancer fear and fatalism

Little is known about the correlates of cancer information avoidance and whether people with negative feelings and beliefs about cancer are more likely to avoid cancer information, allowing such thoughts and feelings to persist unchallenged. Using the Extended Parallel Processing Model as a theoretical guide, we tested the hypothesis that cancer fear and fatalism would predict cancer information avoidance but that part of this effect would be mediated via cancer-specific threat and efficacy beliefs. A community sample of older adults, ages 50 to 70 years (n = 1,442), completed a postal questionnaire that included the Powe Fatalism Inventory and the Champion Cancer Fear scale along with other measures of cancer-specific beliefs and demographic variables. Higher levels of cancer fear were positively associated with higher levels of cancer information avoidance, and part of this relationship was mediated via perceived cancer severity. The relationship between cancer fatalism and cancer information avoidance was partly mediated by severity and response-efficacy beliefs. This research shows that people with negative views about cancer are more likely to avoid cancer information. This means people with higher levels of cancer fear and fatalism are less likely to learn about positive developments made in the field of cancer control, allowing such negative feelings and views to continue. Research needs to focus on how to get positive messages about improvements in cancer prevention and control through to people who are fearful of and fatalistic about the disease.

The Translational Research Working Group developmental pathway for lifestyle alterations

The Translational Research Working Group (TRWG) was created as a national initiative to evaluate the current status of National Cancer Institute's investment in translational research and envision its future. The TRWG conceptualized translational research as a set of six developmental processes or pathways focused on various clinical goals. One of those pathways describes the development of lifestyle alterations, which can, variously, be recommended to prevent cancer, modify a patient's adherence and response to cancer treatment, ameliorate side effects of cancer treatments, or improve prognosis and quality of life in cancer patients and survivors. The lifestyle alteration pathway was conceived not as a comprehensive description of the corresponding real-world processes, but rather as a tool designed to facilitate movement of a candidate lifestyle alteration through the translational process up to the point where it could be handed off for definitive testing, when appropriate. This article discusses key issues associated with the development of lifestyle alterations in light of the pathway.

Antibiotic use predicts an increased risk of cancer

Antibiotic use has been hypothesized to be associated with the risk of cancer but the evidence is sparse and inconsistent. The aim of the present study was to determine whether antibiotic use predicts the development of various cancers. This nationwide cohort study included 3,112,624 individuals, aged 30-79 years, with no history of cancer. Information on their antibiotic use between 1995 and 1997 was obtained from the Drug Prescription Registry. During the period 1998-2004, 134,070 cancer cases were ascertained from the Finnish Cancer Registry. Cox proportional hazards regression was used to estimate the relative risks (RRs) with 95% confidence intervals (95% CIs). Antibiotic use was associated with an increased risk of cancer: for categories of increasing antibiotic use (0-1, 2-5 and >/=6 prescriptions), RRs (95% CIs) for cancer were 1.0 (reference), 1.27 (1.26-1.29) and 1.37 (1.34-1.40). RRs (for comparison of lowest and highest exposure group) for the most common primary sites i.e. prostate, breast, lung and colon were 1.39 (1.31-1.48), 1.14 (1.09-1.20), 1.79 (1.67-1.92), and 1.15 (1.04-1.26), respectively. RRs for other primary sites varied between 0.90 (0.76-1.05) for ovary to 2.60 (1.60-4.20) for endocrine gland (excluding thyroid). In conclusion, antibiotic use predicts an increased risk of cancer. Because of the design of our study the possibility of residual confounding cannot be excluded and further studies are required to confirm the results.

The lipidome as a composite biomarker of the modifiable part of the risk of breast cancer

The potential for dietary fat to prevent breast cancer makes identification of defined molecules a mandatory step. In order to circumvent the limitations and/or bias of dietary exposure assessment tools, we have used the fatty acid composition of white adipose tissue as biomarker of past lipid intake. When considered separately, candidate fatty acids identified as favourable on the basis of their association with breast cancer risk have usually led to inconsistent results in dietary intervention studies carried out in rats. This inconsistency indicates that any approach based on a single fatty acid should be abandoned for an integrated view over the complex lipid interactions, which finally determines the lipidome, the lipid profile that is found in individuals. We reappraised the role of the complete lipid profile through a comprehensive study of adipose tissue fatty acids obtained in patients with benign or malignant breast tumors. Rather than a single fatty acid, a composite indicator combining elevated monounsaturates and low n-6/n-3 fatty acid ratio was associated with decreased breast cancer risk. The lipidome may provide the opportunity to quantify the modifiable part of the risk of breast cancer. The lipidome may be used as a template for designing proper dietary modifications in order to delay the occurrence of breast cancer. Which dietary modifications should be undertaken in order to bring a pertinent change to the lipidome with respect to the risk of breast cancer is currently unknown. The lipidome may allow the individualization of a high risk population of women, who may be targeted for a dietary prevention of breast cancer. The setting and validation of a high-throughput lipidomic station with analytical capabilities fitted to the need of mass screening is required. These two locks must be resolved before a primary prevention of breast cancer by diet could be contemplated.