Epidemiological science and cancer control

Epidemiological methods are essential for the discovery of cancer risks and prognostic factors as well as for the evaluation of cancer prevention measures. In this review, we discuss epidemiological surveillance procedures for data collection and processing to guide and evaluate the consequences of anticancer efforts for populations, assess the identification of cancer risk factors, examine barriers to cancer screening and recommended rules for early diagnosis programs. Epidemiological studies have shown that hindrances to cancer information assessment are currently encountered in developing countries. Known cancer risk factors include social determinants, lifestyle factors, occupational exposures, infectious agents, and genetic and epigenetic alterations. Challenges remain in studying the effectiveness of cancer screening; screening can have detrimental effects, and few cancers clearly benefit from screening. Currently, epidemiology faces the challenge of dealing with distinct levels of data, including factors related to social status, lifestyle and genetics, to reconstruct the causal traits of cancer. Additionally, translating epidemiological knowledge into cancer control demands more implementation studies in the population

Infection and childhood leukemia: review of evidence

OBJETIVO : Analisar estudos que avaliaram o papel de infecções e de medidas indiretas de exposição às infecções no risco de leucemia infantil, principalmente da leucemia linfocítica aguda. MÉTODOS : A busca nas bases de dados Medline, Lilacs e SciELO utilizando-se inicialmente os descritores “leucemia infantil” e “infecção” e, posteriormente, pesquisando-se as palavras “leucemia infantil” e “infecção ou doença materna” ou “aleitamento materno” ou “frequência à creche” ou “vacinação” recuperou 62 publicações que atenderam aos seguintes critérios de inclusão: amostra composta por sujeitos com idade inferior ou igual a 15 anos; análise específica de casos diagnosticados com leucemia linfocítica aguda ou todas as leucemias; avaliação de exposição materna ou infantil a infecções (ou medidas indiretas de exposição à infecção) e risco de leucemia. RESULTADOS : Globalmente, os 23 estudos que avaliaram infecções nas crianças suportam a hipótese de que a ocorrência de infecções no início da infância reduz o risco de leucemia, mas existem discordâncias intra e entre estudos. A avaliação por meio das medidas indiretas de exposição à infecção mostrou evidências de redução do risco de leucemia associado principalmente com frequência à creche. Mais de 50,0% dos 16 estudos que avaliaram exposição materna à infecção observaram aumento do risco de leucemia associado com episódios de gripe, pneumonia, varicela, herpes zoster, infecção do trato genital inferior, doença de pele, doenças sexualmente transmissíveis, vírus Epstein-Barr (EBV) e Helicobacter pylori . CONCLUSÕES : Embora nenhum agente infeccioso específico tenha sido identificado, as evidências científicas são sugestivas de que a exposição a infecções interfere na etiologia da leucemia infantil.OBJETIVO : Analizar estudios que evaluaron el papel de infecciones y de medidas indirectas de exposición a las infecciones en el riesgo de leucemia infantil, principalmente de la leucemia linfocítica aguda. MÉTODOS : Se realizó búsqueda en las bases de datos Medline, LILACS y SciELO utilizándose inicialmente los descriptores “leucemia infantil” e “infección” y, posteriormente, investigándose las palabras “leucemia infantil” e “infección o enfermedad materna” o “lactancia materna” o “frecuencia en guardería” o “vacunación” recuperó 62 publicaciones que atendieron los siguientes criterios de inclusión: muestra compuesta por individuos con edad inferior o igual a 15 años; análisis específica de casos diagnosticados con leucemia linfocítica aguda o todas las leucemias; evaluación de exposición materna o infantil a infecciones (o medidas indirectas de exposición a la infección) y riesgo de leucemia. RESULTADOS : Globalmente, los 23 estudios que evaluaron infecciones en los niños soportan la hipótesis de que la ocurrencia de infecciones en el inicio de la infancia reduce el riesgo de leucemia, pero existen discordancias intra y entre estudios. La evaluación por medio de las medidas indirectas de exposición a la infección mostró evidencias de reducción de riesgo de leucemia asociado principalmente con frecuencia a la guardería. Más de 50% de los 16 estudios que evaluaron exposición materna a la infección observaron aumento de riesgo de leucemia asociado con episodios de gripe, neumonía, varicela, herpes zoster, infección del tracto genital inferior, enfermedad de la piel, enfermedades sexualmente transmisibles, virus Epstein-Barr (EBV) y Helicobacter pylori. CONCLUSIONES : A pesar de que ningún agente infeccioso específico haya sido identificado, las evidencias científicas sugieren que la exposición a infecciones interfiere en la etiología de la leucemia infantil.OBJECTIVE : To analyze studies that evaluated the role of infections as well as indirect measures of exposure to infection in the risk of childhood leukemia, particularly acute lymphoblastic leukemia. METHODS : A search in Medline, Lilacs, and SciELO scientific publication databases initially using the descriptors “childhood leukemia” and “infection” and later searching for the words “childhood leukemia” and “maternal infection or disease” or “breastfeeding” or “daycare attendance” or “vaccination” resulted in 62 publications that met the following inclusion criteria: subject aged ≤ 15 years; specific analysis of cases diagnosed with acute lymphoblastic leukemia or total leukemia; exposure assessment of mothers’ or infants’ to infections (or proxy of infection), and risk of leukemia. RESULTS : Overall, 23 studies that assessed infections in children support the hypothesis that occurrence of infection during early childhood reduces the risk of leukemia, but there are disagreements within and between studies. The evaluation of exposure to infection by indirect measures showed evidence of reduced risk of leukemia associated mainly with daycare attendance. More than 50.0% of the 16 studies that assessed maternal exposure to infection observed increased risk of leukemia associated with episodes of influenza, pneumonia, chickenpox, herpes zoster, lower genital tract infection, skin disease, sexually transmitted diseases, Epstein-Barr virus, and Helicobacter pylori . CONCLUSIONS : Although no specific infectious agent has been identified, scientific evidence suggests that exposure to infections has some effect on childhood leukemia etiology

Infection and childhood leukemia: review of evidence

OBJECTIVE : To analyze studies that evaluated the role of infections as well as indirect measures of exposure to infection in the risk of childhood leukemia, particularly acute lymphoblastic leukemia. METHODS : A search in Medline, Lilacs, and SciELO scientific publication databases initially using the descriptors “childhood leukemia” and “infection” and later searching for the words “childhood leukemia” and “maternal infection or disease” or “breastfeeding” or “daycare attendance” or “vaccination” resulted in 62 publications that met the following inclusion criteria: subject aged ≤ 15 years; specific analysis of cases diagnosed with acute lymphoblastic leukemia or total leukemia; exposure assessment of mothers’ or infants’ to infections (or proxy of infection), and risk of leukemia. RESULTS : Overall, 23 studies that assessed infections in children support the hypothesis that occurrence of infection during early childhood reduces the risk of leukemia, but there are disagreements within and between studies. The evaluation of exposure to infection by indirect measures showed evidence of reduced risk of leukemia associated mainly with daycare attendance. More than 50.0% of the 16 studies that assessed maternal exposure to infection observed increased risk of leukemia associated with episodes of influenza, pneumonia, chickenpox, herpes zoster, lower genital tract infection, skin disease, sexually transmitted diseases, Epstein-Barr virus, and Helicobacter pylori . CONCLUSIONS : Although no specific infectious agent has been identified, scientific evidence suggests that exposure to infections has some effect on childhood leukemia etiology

Diabetes mellitus, metformin and head and neck cancer

Introduction: Diabetes mellitus (DM (Diabetes Mellitus)) is directly associated with some cancers. However, studies on the association between diabetes mellitus and head and neck cancer (HNC (Head and Neck Cancer)) have rendered controversial results. The objective of this study was to evaluate the association between DM and HNC, as well as the impact of metformin use on the risk of HNC. Material and methods: This case-control study was conducted within the framework of the Brazilian Head and Neck Genome Project in 2011-2014. The study included 1021 HNC cases with histologically confirmed squamous cell carcinoma of the head and neck admitted to five large hospitals in Sao Paulo state. A total of 1063 controls were selected in the same hospitals. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression. Results: Diabetic participants had a decreased risk of HNC (OR = 0.68; 95% CI: 0.49-0.95) than nondiabetic participants, and this risk was further decreased among diabetic metformin users (OR = 0.54; 95% CI: 0.29-0.99). Diabetic metformin users that were current smokers (OR = 0.13; 95% CI: 0.04-0.44) or had an alcohol consumption of >40 g/day (OR = 0.31; 95% CI: 0.11-0.88) had lower risk of HNC than equivalent non-diabetic participants. Conclusion: The risk of HNC was decreased among diabetic participants; metformin use may at least partially explain this inverse association. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe

High-throughput sequencing of small RNA transcriptomes reveals critical biological features targeted by microRNAs in cell models used for squamous cell cancer research

Abstract\ud \ud \ud \ud Background\ud \ud The implication of post-transcriptional regulation by microRNAs in molecular mechanisms underlying cancer disease is well documented. However, their interference at the cellular level is not fully explored. Functional in vitro studies are fundamental for the comprehension of their role; nevertheless results are highly dependable on the adopted cellular model. Next generation small RNA transcriptomic sequencing data of a tumor cell line and keratinocytes derived from primary culture was generated in order to characterize the microRNA content of these systems, thus helping in their understanding. Both constitute cell models for functional studies of microRNAs in head and neck squamous cell carcinoma (HNSCC), a smoking-related cancer. Known microRNAs were quantified and analyzed in the context of gene regulation. New microRNAs were investigated using similarity and structural search, ab initio classification, and prediction of the location of mature microRNAs within would-be precursor sequences. Results were compared with small RNA transcriptomic sequences from HNSCC samples in order to access the applicability of these cell models for cancer phenotype comprehension and for novel molecule discovery.\ud \ud \ud \ud Results\ud \ud Ten miRNAs represented over 70% of the mature molecules present in each of the cell types. The most expressed molecules were miR-21, miR-24 and miR-205, Accordingly; miR-21 and miR-205 have been previously shown to play a role in epithelial cell biology. Although miR-21 has been implicated in cancer development, and evaluated as a biomarker in HNSCC progression, no significant expression differences were seen between cell types. We demonstrate that differentially expressed mature miRNAs target cell differentiation and apoptosis related biological processes, indicating that they might represent, with acceptable accuracy, the genetic context from which they derive. Most miRNAs identified in the cancer cell line and in keratinocytes were present in tumor samples and cancer-free samples, respectively, with miR-21, miR-24 and miR-205 still among the most prevalent molecules at all instances. Thirteen miRNA-like structures, containing reads identified by the deep sequencing, were predicted from putative miRNA precursor sequences. Strong evidences suggest that one of them could be a new miRNA. This molecule was mostly expressed in the tumor cell line and HNSCC samples indicating a possible biological function in cancer.\ud \ud \ud \ud Conclusions\ud \ud Critical biological features of cells must be fully understood before they can be chosen as models for functional studies. Expression levels of miRNAs relate to cell type and tissue context. This study provides insights on miRNA content of two cell models used for cancer research. Pathways commonly deregulated in HNSCC might be targeted by most expressed and also by differentially expressed miRNAs. Results indicate that the use of cell models for cancer research demands careful assessment of underlying molecular characteristics for proper data interpretation. Additionally, one new miRNA-like molecule with a potential role in cancer was identified in the cell lines and clinical samples.The authors acknowledge the contribution of GENCAPO (Brazilian Head and Neck Genome Project) for clinical samples and for clinical and pathological data collection (complete list of members and affiliations presented athttp://www.gencapo.famerp.br). This work was supported by FAPESP (grants 09/04166-5 and 10/51168-0) and by Hospital Israelita Albert Einstein

MicroRNA expression profile in head and neck cancer: HOX-cluster embedded microRNA-196a and microRNA-10b dysregulation implicated in cell proliferation

Abstract\ud \ud \ud \ud Background\ud Current evidence implicates aberrant microRNA expression patterns in human malignancies; measurement of microRNA expression may have diagnostic and prognostic applications. Roles for microRNAs in head and neck squamous cell carcinomas (HNSCC) are largely unknown. HNSCC, a smoking-related cancer, is one of the most common malignancies worldwide but reliable diagnostic and prognostic markers have not been discovered so far. Some studies have evaluated the potential use of microRNA as biomarkers with clinical application in HNSCC.\ud \ud \ud \ud Methods\ud MicroRNA expression profile of oral squamous cell carcinoma samples was determined by means of DNA microarrays. We also performed gain-of-function assays for two differentially expressed microRNA using two squamous cell carcinoma cell lines and normal oral keratinocytes. The effect of the over-expression of these molecules was evaluated by means of global gene expression profiling and cell proliferation assessment.\ud \ud \ud \ud Results\ud Altered microRNA expression was detected for a total of 72 microRNAs. Among these we found well studied molecules, such as the miR-17-92 cluster, comprising potent oncogenic microRNA, and miR-34, recently found to interact with p53. HOX-cluster embedded miR-196a/b and miR-10b were up- and down-regulated, respectively, in tumor samples. Since validated HOX gene targets for these microRNAs are not consistently deregulated in HNSCC, we performed gain-of-function experiments, in an attempt to outline their possible role. Our results suggest that both molecules interfere in cell proliferation through distinct processes, possibly targeting a small set of genes involved in cell cycle progression.\ud \ud \ud \ud Conclusions\ud Functional data on miRNAs in HNSCC is still scarce. Our data corroborate current literature and brings new insights into the role of microRNAs in HNSCC. We also show that miR-196a and miR-10b, not previously associated with HNSCC, may play an oncogenic role in this disease through the deregulation of cell proliferation. The study of microRNA alterations in HNSCC is an essential step to the mechanistic understanding of tumor formation and could lead to the discovery of clinically relevant biomarkers.Financial support was provided by Fundaçao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESP (05/51467-0 and 09/04166-5) and Albert Einstein Research and Education Institute – IIEP (IEP.PE.08-0125). CC and JR were funded by The Wellcome Trust. The authors acknowledge Dr. Flavio Borges for statistical analysis of miRNA expression and clinical data. The authors acknowledge the contribution of the GENCAPO (Brazilian Head and Neck Genome Project) for sample collection, clinical and pathological data collection and interpretation, and fruitful discussions (complete list of members and affiliations presented at http://www.gencapo.famerp.br)

Effect of HPV on head and neck cancer patient survival, by region and tumor site: A comparison of 1362 cases across three continents

Objectives: To explore whether HPV-related biomarkers predict oropharyngeal squamous cell cancer (OPSCC) survival similarly across different global regions, and to explore their prognostic utility among non-oropharyngeal (non-OP) head and neck cancers. Methods: Data from 1362 head and neck SCC (HNSCC) diagnosed 2002–2011 was used from epidemiologic studies in: Brazil (GENCAPO study, n = 388), U.S. (CHANCE study, n = 472), and Europe (ARCAGE study, n = 502). Tumors were centrally tested for p16INK4a and HPV16 DNA (by PCR). Risk of mortality was examined using Cox proportional hazard models. Results: There were 517 OPSCC and 845 non-OP HNSCC. Cases were primarily male (81%), ever smokers (91%), with median age of 58 years and median follow-up of 3.1 years (IQR = 1.4–5.9). Among OPSCC, the risk of mortality was significantly lower among 184 HPV-related (i.e., p16+/HPV16+) compared to 333 HPV-unrelated (p16- and/or HPV16-) cases (HR = 0.25, 95%CI = 0.18–0.34). Mortality was reduced among HPV-related OPSCC cases from the U.S., Europe, and Brazil (each p ⩽ 0.01) and after adjustment, remained significantly reduced (aHR = 0.34, 95%CI = 0.24–0.49). Among non-OP HNSCC, neither p16 (aHR = 0.83, 95%CI = 0.60–1.14), HPV16 DNA (aHR = 1.20, 95%CI = 0.89–1.63), or p16+/HPV16+ (aHR = 0.59, 95%CI = 0.32–1.08) was a significantly predictor of mortality. When interaction was tested, the effect of HPV16/p16 was significantly different in OPSCC than non-OP HNSCC (p-interaction = 0.02). Conclusion: HPV-related OPSCCs had similar survival benefits across these three regions. Prognostic utility of HPV among non-OP HNSCC is limited so tumor HPV/p16 testing should not be routinely done among non-OP HNSCC

Mouthwash use and cancer of the head and neck: a pooled analysis from the International Head and Neck Cancer Epidemiology Consortium

Most mouthwashes contain alcohol, a known cause of head and neck cancer (oral cavity, pharynx, larynx), likely through the carcinogenic activity of acetaldehyde, formed in the oral cavity from alcohol

Occupational socioeconomic risk associations for head and neck cancer in Europe and South America: individual participant data analysis of pooled case–control studies within the INHANCE Consortium

Background: The association between socioeconomic disadvantage (low education and/or income) and head and neck cancer is well established, with smoking and alcohol consumption explaining up to three-quarters of the risk. We aimed to investigate the nature of and explanations for head and neck cancer risk associated with occupational socioeconomic prestige (a perceptual measure of psychosocial status), occupational socioeconomic position and manual-work experience, and to assess the potential explanatory role of occupational exposures. Methods: Pooled analysis included 5818 patients with head and neck cancer (and 7326 control participants) from five studies in Europe and South America. Lifetime job histories were coded to: (1) occupational social prestige-Treiman's Standard International Occupational Prestige Scale (SIOPS); (2) occupational socioeconomic position-International Socio-Economic Index (ISEI); and (3) manual/non-manual jobs. Results: For the longest held job, adjusting for smoking, alcohol and nature of occupation, increased head and neck cancer risk estimates were observed for low SIOPS OR=1.88 (95% CI: 1.64 to 2.17), low ISEI OR=1.74 (95% CI: 1.51 to 1.99) and manual occupations OR=1.49 (95% CI: 1.35 to 1.64). Following mutual adjustment by socioeconomic exposures, risk associated with low SIOPS remained OR=1.59 (95% CI: 1.30 to 1.94). Conclusions: These findings indicate that low occupational socioeconomic prestige, position and manual work are associated with head and neck cancer, and such risks are only partly explained by smoking, alcohol and occupational exposures. Perceptual occupational psychosocial status (SIOPS) appears to be the strongest socioeconomic factor, relative to socioeconomic position and manual/non-manual work

Body mass index and risk of head and neck cancer in a pooled analysis of case-control studies in the International Head and Neck Cancer Epidemiology (INHANCE) Consortium

Background Head and neck cancer (HNC) risk is elevated among lean people and reduced among overweight or obese people in some studies; however, it is unknown whether these associations differ for certain subgroups or are influenced by residual confounding from the effects of alcohol and tobacco use or by other sources of biases. Methods We pooled data from 17 case-control studies including 12 716 cases and the 17 438 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for associations between body mass index (BMI) at different ages and HNC risk, adjusted for age, sex, centre, race, education, tobacco smoking and alcohol consumption. Results Adjusted ORs (95% CIs) were elevated for people with BMI at reference (date of diagnosis for cases and date of selection for controls) ≤18.5 kg/m2 (2.13, 1.75-2.58) and reduced for BMI >25.0-30.0 kg/m2 (0.52, 0.44-0.60) and BMI ≥30 kg/m2 (0.43, 0.33-0.57), compared with BMI >18.5-25.0 kg/m2. These associations did not differ by age, sex, tumour site or control source. Although the increased risk among people with BMI ≤18.5 kg/m2 was not modified by tobacco smoking or alcohol drinking, the inverse association for people with BMI > 25 kg/m2 was present only in smokers and drinkers. Conclusions In our large pooled analysis, leanness was associated with increased HNC risk regardless of smoking and drinking status, although reverse causality cannot be excluded. The reduced risk among overweight or obese people may indicate body size is a modifier of the risk associated with smoking and drinking. Further clarification may be provided by analyses of prospective cohort and mechanistic studie