Subtypes of Native American ancestry and leading causes of death: Mapuche ancestry-specific associations with gallbladder cancer risk in Chile.

Latin Americans are highly heterogeneous regarding the type of Native American ancestry. Consideration of specific associations with common diseases may lead to substantial advances in unraveling of disease etiology and disease prevention. Here we investigate possible associations between the type of Native American ancestry and leading causes of death. After an aggregate-data study based on genome-wide genotype data from 1805 admixed Chileans and 639,789 deaths, we validate an identified association with gallbladder cancer relying on individual data from 64 gallbladder cancer patients, with and without a family history, and 170 healthy controls. Native American proportions were markedly underestimated when the two main types of Native American ancestry in Chile, originated from the Mapuche and Aymara indigenous peoples, were combined together. Consideration of the type of Native American ancestry was crucial to identify disease associations. Native American ancestry showed no association with gallbladder cancer mortality (P = 0.26). By contrast, each 1% increase in the Mapuche proportion represented a 3.7% increased mortality risk by gallbladder cancer (95%CI 3.1-4.3%, P = 6×10-27). Individual-data results and extensive sensitivity analyses confirmed the association between Mapuche ancestry and gallbladder cancer. Increasing Mapuche proportions were also associated with an increased mortality due to asthma and, interestingly, with a decreased mortality by diabetes. The mortality due to skin, bladder, larynx, bronchus and lung cancers increased with increasing Aymara proportions. Described methods should be considered in future studies on human population genetics and human health. Complementary individual-based studies are needed to apportion the genetic and non-genetic components of associations identified relying on aggregate-data.

ABCB1/4 gallbladder cancer risk variants identified in India also show strong effects in Chileans.

BACKGROUND: The first large-scale genome-wide association study of gallbladder cancer (GBC) recently identified and validated three susceptibility variants in the ABCB1 and ABCB4 genes for individuals of Indian descent. We investigated whether these variants were also associated with GBC risk in Chileans, who show the highest incidence of GBC worldwide, and in Europeans with a low GBC incidence. METHODS: This population-based study analysed genotype data from retrospective Chilean case-control (255 cases, 2042 controls) and prospective European cohort (108 cases, 181 controls) samples consistently with the original publication. RESULTS: Our results confirmed the reported associations for Chileans with similar risk effects. Particularly strong associations (per-allele odds ratios close to 2) were observed for Chileans with high Native American (=Mapuche) ancestry. No associations were noticed for Europeans, but the statistical power was low. CONCLUSION: Taking full advantage of genetic and ethnic differences in GBC risk may improve the efficiency of current prevention programs.

Actualización en cáncer de próstata: generalidades y diagnóstico / Update in prostate cancer: overview and diagnosis

Resumen: El cáncer de próstata es una enfermedad clínicamente caracterizada por un periodode latencia largo y un crecimiento tumoral lento. En la actualidad, es un problema de granimportancia para la salud pública, pues es el segundo cáncer más frecuentemente diagnosticadoy corresponde a la sexta causa de muerte por cáncer en hombres en el mundo. Se caracteriza poruna gran heterogeneidad clínica y molecular. Su diagnóstico se basa en el uso de tres pruebasfundamentales: el examen del tacto rectal y la medición de los niveles séricos del antígenoespecífico de próstata (AEP), los cuales se usan frecuentemente en el tamizaje, y la biopsiaprostática, mediante la cual se confirma el diagnóstico de cáncer de próstata. Actualmente, el AEPse ha constituido en la principal herramienta tamiz para el cáncer de próstata; no obstante, existeuna gran controversia en torno a su uso. Por ello, están siendo ampliamente estudiados nuevosbiomarcadores, a fin de disponer de pruebas diagnósticas más sensibles y específicas. Dado queel AEP es una prueba ampliamente utilizada internacionalmente y que han surgido biomarcadoresadicionales para el diagnóstico temprano del cáncer de próstata, es de fundamental importanciaque el personal de la salud en general y el personal de laboratorio en particular puedan contarcon información con respecto al uso de éstas y su relación con otras herramientas diagnósticas,además de otros aspectos generales del cáncer de próstata.

Abstract: Prostate cancer is a disease clinically characterized by a long latency period and slow tumorgrowth rate. Prostate cancer is currently a major public health problem because it is the second mostcommonly diagnosed cancer, and the sixth major cause of cancer-related death in men in the world.It is characterized by clinical and molecular heterogeneity. Diagnosis is based on the use of threebasic tests: digital rectal examination, measurement of prostate-specific antigen (PSA) serum levels,frequently used in screening, and prostate biopsy, which confirms the diagnosis of prostate cancer.Nowadays, PSA has become the main testing way for prostate cancer screening, although there ismuch controversy about its use. Therefore, new biomarkers are being widely researched, in order toprovide more sensitive and more specific diagnostic tests. Provided that PSA is a globally used test,and additional tests for early diagnosis of prostate cancer have aroused, is it essential that healthpersonnel, and particularly laboratory personnel, are granted with information about their use, andtheir relationship with further diagnostic techniques, besides other general aspects of prostate cancer.

Colonización por Staphylococcus aureus resistentea meticilina en las manos de individuosde la comunidad / Hand colonization by methicillin-resistant Staphylococcus aureus (MRSA) in the community

En la última década han sido cada vez más frecuentes los informes de infecciones causadas porcepas de Staphylococcus aureus resistente a meticilina asociadas a la comunidad (CA-MRSA,por Community-associated methicillin-resistant S. aureus). La colonización juega un papelimportante en la epidemiología de tales infecciones. Sin embargo, los estudios de colonizaciónse han centrado principalmente en el ambiente hospitalario y se han hecho muy pocos en lacomunidad. En este trabajo se investigó la frecuencia de colonización por S. aureus en generaly por MRSA en las manos de individuos de la población general no relacionados con el área dela salud, empleando métodos fenotípicos y moleculares. Se obtuvieron mediante hisopado 800muestras de las manos de otros tantos individuos. Se halló colonización por Staphylococcusaureus en 65 muestras (8,1%) y por MRSA en 5 (0,63%). Las 5 cepas de MRSA presentaban elcasete cromosómico mec (SCCmec) de los tipos IV o V, típicamente relacionados con CA-MRSA.Nuestro trabajo evidenció la colonización de las manos por MRSA en individuos de la comunidad,lo cual constituye un importante factor de riesgo, no solo por su asociación con el desarrolloulterior de infecciones, sino también por el potencial de diseminar este microorganismo a lapoblación general.

Community-associated methicillin-resistant Staphylococcus aureus infections (CA-MRSA) havebeen reported with increasing frequency during the past decade. Colonization plays an importantrole in the epidemiology of such infections. However, colonization studies have focused mostlyon hospital settings and only a few have been carried out in communities. This was a study of thefrequency of hand colonization by S. aureus in generaland by CA-MRSA, by means of phenotypical andmolecular methods, in 800 adults from the communitywho had no relationship with the health area.Staphylococcus aureus colonization was found in 65individuals (8.1%) and MRSA was present in 5 (0.63%).The 5 MRSA strains were found to have mecchromosomic cassettes (SCCmec) of either type IV orV, typical of CA-MRSA. Our study provides evidence ofCA-MRSA colonization in the hands of individuals fromthe community. This constitutes an important riskfactor, not only by its association with subsequentinfections, but also for the risk of dissemination of thismicroorganism to the general population.