Cáncer colorrectal. Variantes génicas en la vía de señalización BMP y ancestría en población mexicana / Colorectal cancer. Genetic variants in BMP signaling pathway and ancestry in the Mexican population

Resumen Introducción: Variantes génicas relacionadas con la vía de señalización de las proteínas morfogenéticas óseas (BMP2, BMP4, GREM1, SMAD7) se han asociado a cáncer colorrectal, principalmente en poblaciones caucásicas. Objetivo: Describir la asociación de variantes en miembros de la vía BMP en población mexicana, caracterizada por su ancestría indoamericana y caucásica. Métodos: Se realizó el genotipado de 1000 casos de cáncer colorrectal y 1043 individuos de control reclutados en la Ciudad de México, Monterrey y Torreón mediante la plataforma Sequenom. Con análisis univariados y multivariados se estudiaron las asociaciones entre cáncer colorrectal y variantes. Resultados: Las variantes rs4444235, rs12953717 y rs4939827 replicaron la asociación con la neoplasia (p ≤ 0.05). La ascendencia caucásica mostró asociación con el tumor. Conclusiones: El estudio mostró las asociaciones entre cáncer colorrectal y las variantes SMAD7 y BMP4, así como con el componente caucásico de la mezcla étnica.

Abstract Introduction: Genetic variants related to bone morphogenetic proteins (BMP2, BMP4, GREM1, SMAD7) signaling pathway have been associated with colorectal cancer, mainly in Caucasian populations. Objective: To describe the association of variants in members of the BMP signaling pathway in a Mexican population, characterized by its indigenous American and Caucasian ancestry. Methods: Genotyping of 1,000 colorectal cancer cases and 1,043 control individuals recruited in Mexico City, Monterrey, and Torreón was carried out using the Sequenom platform. Associations between colorectal cancer and variants were studied with univariate and multivariate analyses. Results: Variants rs4444235, rs12953717 and rs4939827 replicated the association with the neoplasm (p ≤ 0.05). Caucasian ancestry showed association with the tumor. Conclusions: The study replicated the associations between colorectal cancer and SMAD7 and BMP4 variants, with an association being observed with the Caucasian component of the ethnic mix.

Tipificación de serotipos del virus del papiloma humano de alto riesgo / Typification of high-risk human papilomavirus serotypes

Resumen: OBJETIVO: Identificar los serotipos más frecuentes de virus del papiloma humano mediante pruebas al azar en pacientes previamente diagnosticadas con cáncer cervicouterino. MATERIALES Y MÉTODOS: Estudio prospectivo y observacional, efectuado en pacientes con displasia cervical, atendidas en el Hospital Regional Materno Infantil de Alta Especialidad de Nuevo León, Monterrey, entre enero y marzo de 2016. Criterios de inclusión: pacientes mayores de 18 años, que acudieron a la unidad médica para seguimiento y control ginecológico, con reporte anormal en la prueba de Papanicolaou, confirmado por histopatología, mediante biopsia dirigida por colposcopia. Criterios de exclusión: mujeres con histerectomía total por indicación de enfermedad benigna, sin antecedente de neoplasia intracervical; mayores a 70 años después de 3 citologías cervicales negativas en la década previa; pacientes que recibieron quimioterapia, radioterapia u otros tratamientos farmacológicos y quienes acudieron a revisión médica durante su ciclo menstrual. Para el análisis de los datos se utilizó estadística descriptiva. RESULTADOS: Se registraron 30 pacientes. Las clasificaciones más frecuentes de neoplasia cervical fueron: NIC-1 (n = 15), NIC-2 (n = 9) y NIC-3 (n = 6). Todas las pacientes analizadas tuvieron, al menos, un serotipo de VPH de alto riesgo. Los serotipos identificados con mayor frecuencia fueron el 31 y 33 (n = 18). En 18 pacientes se encontraron 6 o más serotipos de VPH. De 15 pacientes con lesiones de alto grado, 8 tuvieron la asociación de serotipos 31 y 33, y en 6 se identificó un serotipo aislado (16 y 51). CONCLUSIONES: Los serotipos identificados con mayor frecuencia fueron el 31 y 33. Desafortunadamente, la vacuna nonavalente que protege contra los serotipos más frecuentes de VPH no se encuentra disponible en Latinoamérica.

Abstract: OBJECTIVE: To identify the most frequent serotypes of human papillomavirus through random testing of patients previously diagnosed with cervical cancer. MATERIALS AND METHODS: A prospective, observational study carried out in patients with cervical dysplasia, treated at the High Specialty Regional Maternal and Child Hospital of Nuevo León, Monterrey. Inclusion criteria: patients over 18 years of age, who attended the Dysplasia Clinic of the High Specialty Regional Maternal and Child Hospital for gynecological follow-up and control, with an abnormal result in the Papanicolaou test, confirmed by histopathology, by means of colposcopy-directed biopsy. Before the procedures (cervical cytology), Exclusion criteria: women with total hysterectomy due to indications of benign disease, without a history of intracervical neoplasia; older than 70 years after 3 negative cervical cytology in the previous decade; patients who received chemotherapy, radiotherapy or other pharmacological treatments and who received medical check-ups during their menstrual cycle. Descriptive statistics were used for data analysis. RESULTS: 30 patients were registered. The most frequent classification of cervical neoplasia was: CIN1 (n = 15), CIN2 (n = 9) and CIN3 (n = 6). All the patients analyzed had at least one high-risk HPV serotype. The most frequently identified serotypes were 31 and 33 (n = 18 of 30). 6 or more HPV serotypes were found in 18 patients. Of 15 patients with high-grade lesions, 8 had the association of serotypes 31 and 33, and in 6 an isolated serotype was identified (16 and 51). CONCLUSIONS: The most frequently identified serotypes were 31 and 33. Unfortunately, the nonavalent vaccine that protects against the most frequent serotypes of HPV is not available in Latin America.

Evaluation of skin expression profiles of patients with vitiligo treated with narrow-band UVB therapy by targeted RNA-seq

Abstract: Background: Vitiligo is characterized by a lack of pigmentation in the skin. To date, there are no studies that analyze the changes in gene expression in the skin of vitiligo patients in response to narrow-band ultraviolet B (nb-UVB) phototherapy treatment. Objective: Explore the usefulness of new generation RNA sequencing in the identification of gene expression changes in the skin of vitiligo patients treated with nb-UVB phototherapy. Methods: Four skin biopsies (4mm in diameter) were collected from 45 Mexican vitiligo vulgaris patients, 2 specimens before and 2 after treatment with nb-UVB phototherapy, obtained from pigmented and non-pigmented tissue. RNA extracted from the biopsies was analyzed using the Illumina TruSeq Targeted RNA Expression protocol to study the expression of genes that participate in pathways of skin homeostasis. The 2 groups were compared using Student's t-test and the Mann-Whitney U-test. Results: The expression analysis identified differences in 12 genes included in this study after comparing the samples obtained before and after treatment: 5 genes involved in skin pigmentation, 2 genes involved in apoptosis, 2 genes involved in cell survival, 2 genes involved in oxidative stress responses and 1 gene involved in signal transduction mechanisms (p<0.05). Study limitations: The small size of skin biopsies limits the amount of RNA obtained, the number of genes to be analyzed and the use of conventional techniques such as RT-qPCR. Conclusion: We demonstrated usefulness of new generation RNA sequencing in the identification of gene expression changes, in addition to identifying new targets in the study of vitiligo.

Genetic and molecular aspects of androgenetic alopecia

Androgenetic alopecia is the most common form of progressive hair loss in humans. A genetic predisposition and hormonal status are considered as major risk factors for this condition. Several recent advances in molecular biology and genetics have increased our understanding of the mechanisms of hair loss in androgenetic alopecia. We review these advances and examine the trends in the genetic and molecular aspects of androgenetic alopecia.

Análisis de frecuencias alélicas y genotípicas de las variantes CYP2A6*12 y rs16969968 de CHRNA5 y su asociación con el hábito de fumar y el índice de masa corporal (IMC) en sujetos jóvenes del noreste de México / Association between genotype and allele frequencies of CYP2A6*12 and rs16969968 in CHRNA5 variants with smoking and body mass index in young subjects from Northeast Mexico

Background: Several studies have reported that variants rs16969968 G>A of the CHRNA5 gene and CYP2A6*12 of the CYP2A6 gene are associated with smoking and smoking refusal, respectively. In addition, some studies report that a higher cigarette consumption is associated with low body mass index (BMI). Aim: To analyze the allele and genotypic frequencies of these variants and their impact on smoking and BMI. Material and Methods: A blood sample was obtained and a survey about smoking habits was answered by 319 university students aged 18 to 35 years (127 women, 171 smokers), living in Northeastern Mexico. Genetic variants were studied by polymerase chain reaction/restriction fragment length polymorphism and their frequencies were associated with smoking and BMI. Results: No associations were found between the analyzed variants and smoking in the study groups. However, there was an association among non-smoking subjects between the A allele of rs16969968 and high a BMI (p < 0.01). Conclusions: This last variant may be involved in food-addiction disorders.

Farmacogenómica del tratamiento de primera línea en el cáncer gástrico: avances en la identificación de los biomarcadores genómicos de respuesta clínica / Pharmacogenomics of the first-line treatment for gastric cancer: advances in the identification of genomic biomarkers for clinical response to chemotherapy

Debido a la inespecificidad de los síntomas, el cáncer gástrico (CG) es diagnosticado frecuentemente en etapas avanzadas, lo que da cuenta de los altos índices de mortalidad debido a esta neoplasia a nivel mundial. El esquema de tratamiento adyuvante o neoadyuvante en los países occidentales incluye el uso de fluoropirimidinas citotóxicas y compuestos de platino formadores de aductos en el ADN. La respuesta clínica al tratamiento con estos fármacos depende principalmente de la sensibilidad del tumor, la cual a su vez está condicionada por el nivel de expresión de los blancos terapéuticos y de las enzimas de reparación del ADN. Sumado a esto, algunos polimorfismos de línea germinal en genes asociados al metabolismo y a la respuesta a estos fármacos, han mostrado asociación con respuestas pobres y con el desarrollo de eventos adversos, incluso con resultados fatales. La identificación de biomarcadores genómicos, en la forma de polimorfismos genéticos o la expresión diferencial de genes específicos asociados a la respuesta quimioterapeútica ha sido motivo de intensa investigación como base para la aplicación de la farmacogenómica en el establecimiento de una terapia farmacológica racional y personalizada del CG. Sin embargo, ante la eventual aplicación de la farmacogenómica en el ámbito clínico, es necesario establecer el valor pronóstico real de dichos biomarcadores mediante los estudios de asociación genotipo-fenotipo, así como su prevalencia en el contexto de cada población de pacientes. Estos aspectos son indispensables al evaluar la relación costo-efectividad de la introducción de los productos de la medicina genómica predictiva en el tratamiento del CG.

Gastric cancer (GC) is often diagnosed at later stages due to the lack of specificity of symptoms associated with the neoplasm, causing high mortality rates worldwide. The first line of adjuvant and neoadjuvant treatment includes cytotoxic fluoropyrimidines and platin-containing compounds which cause the formation of DNA adducts. The clinical outcome with these antineoplastic agents depends mainly on tumor sensitivity, which is conditioned by the expression level of the drug targets and the DNA-repair system enzymes. In addition, some germ line polymorphisms, in genes linked to drug metabolism and response to chemotherapy, have been associated with poor responses and the development of adverse effects, even with fatal outcomes in GC patients. The identification of genomic biomarkers, such as individual gene polymorphisms or differential expression patterns of specific genes, in a patient-by-patient context with potential clinical application is the main focus of current pharmacogenomic research, which aims at developing a rational and personalized therapy (i.e., a therapy that ensures maximum efficacy with no predictable side effects). However, because of the future application of genomic technologies in the clinical setting, it is necessary to establish the prognostic value of these genomic biomarkers with genotype-phenotype association studies and to evaluate their prevalence in the population under treatment. These issues are important for their cost-effectiveness evaluation, which determines the feasibility of using these medical genomic research products for GC treatment in the clinical setting.

Determinación molecular de marcadores genéticos en síndromes coronarios agudos y su relación con eventos cardiovasculares adversos / Determination of molecular genetic markers in acute coronary syndromes and their relationship to cardiovascular adverse events

Introducción: Algunos genes relacionados con proteínas que participan en algunas rutas metabólicas podrían tener un papel en el desarrollo de los síndromes coronarios agudos. Objetivo: Correlación entre polimorfismos y su relación con eventos adversos en síndromes coronarios agudos. Método: Prospectivo, seguimiento hospitalario y a un año. Inclusión: síndromes coronarios agudos con desnivel o elevación del ST secundario a aterotrombosis, estabilidad clínica. En todos, reacción de cadena de polimerasa y polimorfismos de la longitud de los fragmentos de restricción. Al estandarizar reacciones de cadena y genotipificación se realizó análisis preliminar de distribución de genotipos para cada polimorfismo y en ninguno se observaron desviaciones en la ley de equilibrio de Hardy-Weinberg (p > 0,05). Resultados: De 2003 a 2005 se ingresaron 150 sujetos. Se analizaron 14 polimorfismos en 9 genes (fibrinógeno, factor V, VII, II, XIII, activador e inhibidor del plasminógeno-1 y proteína C reactiva). En síndromes coronarios agudos, un fibrinógeno > 450mg/dL y leucocitos > 8, 500 cél/mm³ fueron marcadores de mal pronóstico a un año. Los análisis de regresión identificaron al -148 CT/TT del fibrinógeno y al -717 AG/GG de la proteína C reactiva como marcadores de isquemia recurrente y al 1691GA+AA para reinfarto. Conclusión: En pacientes con síndromes coronarios agudos se demostró una relación entre polimorfismos relacionados con hemostasia e inflamación con eventos adversos, por lo que podrían considerarse marcadores de enfermedad coronaria. Se requiere una muestra mayor para confirmar estos resultados.

Introduction: The genes coding for proteins due to their activity in several metabolic pathways could be related with the onset of acute coronary syndromes. Objective: Relationship among polymorphisms and adverse events in. Methods: Prospective. In - hospital, one - year follow-up. Inclusion Acute coronary syndromes with ST elevation or depression secondary to atherothrombosis, clinical stability. In all, polymerase chain reaction and length polymorphism of restriction fragments. By standardizing chain reactions and genotyping,a preliminary analysis of distribution of genotypes was performed for each polymorphism and no deviations were observed in the law of Hardy-Weinberg equilibrium (P> .05). Results: From 2003 to 2005, 150 subjects were enrolled. We analyzed 14 polymorphisms in 9 genes (fibrinogen, factor V, VII, II, XIII, plasminogen activator and inhibitor-1, C-reactive protein). In acute coronary syndromes, fibrinogen > 450 mg/dL and white blood count 8500 cells/mm³ were markers of poor prognosis to one year. Regression analysis identified the -148 CT/TT and fibrinogen -717 AG/GG of C-reactive protein as a marker of recurrent ischemia and reinfarction 1691GA +AA. Conclusion: We are showing a relationship among polymorphisms involved in inflammation and hemostasis with adverse events in the acute phase and follow-up in acute coronary syndromes patients that could be considered as markers of ischemic heart disease. Larger sample is needed to confirm these results.

Fibrinógeno. Factor o indicador de riesgo cardiovascular? / Fibrinogen. Cardiovascular risk factor or marker?

Endothelial dysfunction and inflammation play a crucial role in all stages of atherosclerosis, from the beginning, during progression, and, finally, in its highest clinical expression: acute coronary syndromes. In this process, fibrinogen, an acute phase reactant with active participation in endothelial function, thrombosis and inflammation has proved to be an independent variable to cardiovascular risk together with its participation in resistance phenomena to different antithrombotic approaches. The reasons by which fibrinogen is elevated in cardiovascular disease and atherosclerosis are, in general, only incompletely understood; but all cells involved in the atherogenetic process are able to produce cytokines, which induce an acute phase reaction that increases fibrinogen levels in plasma. The potential pathophysiological mechanisms by which elevated fibrinogen levels mediate cardiovascular risk are multiple. Fibrinogen forms the substrate for thrombin an represents the final step in the coagulation cascade, it is essential for platelet aggregation, it modulates endothelial function, it promotes smooth muscle cell proliferation and migration, it interacts with the binding of plasmin with its receptor and, finally, it represents a major acute phase protein. Epidemiological studies have established sufficient evidence to consider fibrinogen as a strong, consistent, and independent cardiovascular risk marker or factor. Based on all these implications, the target of this review is an analysis of physiopathogenic and epidemiologic evidence searching for guidelines to establish whether fibrinogen as a risk factor or marker is the lost link between cardiovascular disease and classic risk factors. CONCLUSION: Analyses of the respective studies suggest that fibrinogen is an important and independent cardiovascular risk factor, clearly associated with conventional risk factors and genetic polymorphisms. Whether or not fibrinogen is causally involved in atherothrombogenesis still remains to be determined and despite of unsolved issues that are waiting conclusive answers, fibrinogen has emerged as an important additional marker of cardiovascular risk.

Interacciones entre polimorfismos del gen MTHFR, gestaciones e inicio de vida sexual modifican el riesgo para cáncer cérvico-uterino en una población del noreste de México / The effect of MTHFR polymorphisms, pregnancy and first intercourse on cervical cancer in a population from the Northeastern Mexico

Objective. To investigate the possible association among MTHFR polymorfhisms, environmental factors and cervical cancer (CC) in the Mexican population. Methods. Seventy patients with CC and 89 control women were questioned about clinical data and their 677 and 1298 genotypes of MTHFR gene were analized. Results. Multipregnancies (0-2 vs. > 3, OR 2.1), an early age of first intercourse (IVS) (17 < vs. > 18 years, OR 4.3) or both factors (OR 3.5) were significantly associated with CC. MTHFR 677, 1298 polymorphisms and their combinations were not different between cases and controls. However, a significant association between pregnancies, TVS and MTHFR polymorphisms (presence of 1298C allele or 677TT genotype) was observed. The 1298C allele plus multipregnancies and IVS < 17 years, or both factors, increased 4.3, 5.3, and 11.8 times the risk for CC, respectively, while 677TT genotype changed the risk 2.0, 1.9, and 4.2 times, respectively. Conclusion. The 1298C allele increases the risk of CC strongly in women with multipregnancies and early age of IVS, while 677TT genotype has a lower risk without becoming a protection factor.

Objetivo. Buscar la asociación entre polimorfismos de la enzima metilentetrahidrofolato reductasa (MTHFR), factores ambientales y cáncer cérvico-uterino (CaCU) en mujeres del noreste de México. Métodos. Setenta pacientes con CaCU y 89 mujeres controles se sometieron a un interrogatorio clínico y a genotipificación de los polimorfismos 677C -> T y 1298A -> C del gen MTHFR. Resultados. La multigestación (0-2 vs.> 3, OR 2.1), un temprano inicio de vida sexual (IVS) (17 < vs. > 18 años, OR 4.3) o la combinación de ambos factores (OR 3.5), estuvieron asociados significativamente al CaCU. Los polimorfismos de MTHFR 677, 1298 y sus combinaciones no fueron diferentes entre casos y controles. Sin embargo, se observó una interacción significativa entre las gestaciones, el IVS y los polimorfismos de MTHFR (presencia del alelo 1298C o del genotipo 677TT). El alelo 1298C combinado con multigestación, con un IVS < 17 años, o con ambos factores, incrementó el riesgo para CaCU en 4.3, 5.3 y 11.8 veces, respectivamente, en tanto que el genotipo 677TT modificó este riesgo a 2.0, 1.9, y 4.2 veces, respectivamente. Conclusión. El alelo 1298C incrementa considerablemente el riesgo para CaCU en mujeres multigestas y con un IVS temprano, en tanto que el genotipo 677TT disminuye este riesgo, pero sin llegar a convertirse en un factor protector.

Mutación 677T del gen MTHFR en adenomas y cáncer colorrectal en una muestra de la población del noreste de México. Resultados Preliminares / 677T mutation of the MTHFR gene in adenomas and colorectal cancer in a sample population in Northeastern Mexico. Preliminary results

Introducción: la ingesta adecuada de folatos puede reducir el riesgo para cáncer de colon. La enzima metilentetrahidrofolato reductasa (MTHFR) juega un papel importante en el metabolismo del folato. El papel de la mutación 677T del gen MTHFR en el riesgo del cáncer de colon es controversial. Recientemente se reportó que la población mexicana presenta una de las frecuencias alélicas más altas del mundo para esta mutación, por lo que resulta interesante analizar si ésta influye en el riesgo de cáncer colorrectal en nuestra población. Objetivo: determinar la frecuencia de la mutación 677T del gen MTHFR en un grupo de pacientes con cáncer de colorrectal y adenomas vs. un grupo control en una muestra de la población en el noreste de México. Método: se procesaron 74 muestras de cáncer colorrectal, 32 adenomas y 110 muestras de controles apareados por edad y sexo. Se realizó extracción de DNA y análisis de la mutación 677T mediante PCR-RFLPs. Resultados: al comparar sujetos portadores de la mutación (homocigotos T/T y heterocigotos C/T) vs. portadores de alelos normales (C/C) se obtiene un riesgo relativo de 1.81 (IC 95 por ciento 0.97 a 3.3), con ? 2 = 3.5 y p = 0.06. Conclusiones: los individuos portadores de la mutación presentan una tendencia hacia un riesgo aumentado para cáncer de colon, lo que sería congruente con el concepto que la deficiencia de folatos contribuye con la patogenia del cáncer colorrectal. La carencia de significancia estadística en este reporte se puede explicar por el tamaño de muestra.