From colorectal cancer pattern to the characterization of individuals at risk: Picture for genetic research in Latin America.

Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency.

Genetic markers in methotrexate treatments.

Methotrexate (MTX), a structural analog of folic acid, is widely employed in the treatment of different cancers and autoimmune diseases. Despite the successful results observed, the main disadvantage lies in interpatient variability in the pharmacokinetic and pharmacodynamic parameters. In particular, adverse events and toxicities induced by MTX are a matter of concern and can be the cause of dose reduction or treatment discontinuation. Among the different approaches to reduce MTX therapeutic limitations, pharmacogenomics contributes by considering the effect of inherited genetic differences on those parameters. This review provides an update on MTX pharmacogenomics. It reports the contribution of main gene polymorphisms involved in the influx, efflux, cellular effect, and elimination on MTX toxicity and efficacy, on all the diseases treated with this drug. From the analysis of the data presented in this review, we concluded that only gene polymorphisms MTHFR rs1801133, SLC19A1 rs1051266, and TYMS rs34743033 could influence clinical decision-making.

Activity of the Calcineurin Pathway in Patients on the Liver Transplantation Waiting List: Factors of Variability and Response to Tacrolimus Inhibition.

BACKGROUND: We sought to evaluate, in patients on a liver transplantation waiting list, potential biomarkers of the base calcineurin pathway activity with use of a new model of nonstimulated peripheral blood mononuclear cells (PBMC) and ex vivo response to tacrolimus (TAC). METHODS: The calcineurin pathway activity was explored ex vivo in stimulated and nonstimulated PBMC from 19 patients. The inhibition of NFAT1 translocation to PBMC nuclei, expression of intracellular IL-2, and membrane CD25 in different T-cell subsets were measured by multiparametric flow cytometry before and after exposure to TAC. We also studied the influence on the individual response of polymorphisms in 3 key genes of the calcineurin pathway: PPIA, PPP3CA, and IL2RA. RESULTS: All pharmacodynamics profiles closely fitted an I/Imax sigmoid model. Interindividual variability was higher in nonstimulated than in stimulated conditions, as well as in the presence of TAC. IL-2+CD8+ cells at TAC Imax showed the highest interindividual variability, suggesting its usefulness as a biomarker of individual TAC effects integrating many different sources of regulation and variability. Moreover, in the absence of TAC, patients with end-stage liver disease exhibited lower NFAT1 translocation and T-cell activation than healthy volunteers from a previous study under similar conditions. Multivariate statistical analysis showed strong and significant associations between TAC pharmacodynamic parameters and 2 polymorphisms in the gene-coding cyclophilin A (rs8177826 and rs6850). CONCLUSIONS: We show the feasibility of using nonstimulated PBMCs to explore the calcineurin pathway under more physiologic conditions and point toward potential biomarkers for TAC pharmacodynamic monitoring. ClinicalTrials.gov Identifier: NCT01760356.

Molecular characterization of genes modifying the age at onset in Huntington's disease in Uruguayan patients.

Huntington's disease (HD) is a hereditary neurodegenerative disorder. The genetic cause is an expansion of CAG repeats located in the IT15 gene. Though the number of CAG repeats ((CAG)n) can largely explain the age at onset (AAO) of symptoms, a percentage of its variation could be attributed to modifier genes and to environmental factors. The study aimed to evaluate the influence of genetic modifiers of the AAO of HD including: (CAG)n and del2642 in the IT15 gene, ADORA2A rs5751876, HAP1 rs4523977, PGC1-α rs7665116 and UCH-L1 rs5030732. Eighteen patients with positive family history and HD-suggestive symptoms were recruited. The (CAG)n and gene polymorphisms were determined by different molecular biology techniques. We observed that the (CAG)n influenced in a 64.5% of the variability in the AAO. We also showed that the rs5751876 variant significantly affected this variability. However, the influence of UCH-L1, del2642, HAP1 and PGC1-α gene polymorphisms could not be replicated, perhaps due to small sample size. Genetic studies including the molecular determination of (CAG)n, in addition to other genetic modifiers involved in the variability of the AAO, were first performed in Uruguay. We could replicate in our cohort the anticipation effect on the AAO by the ADORA2A rs5751876. Our results confirm the usefulness of an expanded molecular characterization in HD patients.

Tacrolimus pharmacodynamics and pharmacogenetics along the calcineurin pathway in human lymphocytes.

BACKGROUND: Although therapeutic drug monitoring has improved the clinical use of immunosuppressive drugs, there is still interpatient variability in efficacy and toxicity that pharmacodynamic monitoring may help to reduce. To select the best biomarkers of tacrolimus pharmacodynamics, we explored the strength and variability of signal transduction and the influence of polymorphisms along the calcineurin pathway. METHODS: Peripheral blood mononuclear cells from 35 healthy volunteers were incubated with tacrolimus (0.1-50 ng/mL) and stimulated ex vivo. Inhibition of NFAT1 (nuclear factor of activated T cells 1) translocation to the nucleus and intracellular expression of interleukin-2 in CD4(+) and CD8(+) T cells and the surface activation marker CD25 in CD3(+) cells were measured by flow cytometry. We sequenced the promoter regions of immunophilins and calcineurin subunits and characterized selected single nucleotide polymorphisms in the genes of the calcineurin pathway with allelic discrimination assays. RESULTS: All responses closely fitted an I/Imax sigmoid model. Large interindividual variability (n = 30) in I0 and IC50 was found for all biomarkers. Moreover, strong and statistically significant associations were found between tacrolimus pharmacodynamic parameters and polymorphisms in the genes coding cyclophilin A, the calcineurin catalytic subunit α isoenzyme, and CD25. CONCLUSIONS: This study demonstrates the consistency and large interindividual variability of signal transduction along the calcineurin pathway, as well as the strong influence of pharmacogenetic polymorphisms in the calcineurin cascade on both the physiological activity of this route and tacrolimus pharmacodynamics.

A comprehensive characterization of the spectrum of MUTYH germline pathogenic variants in Latin America.

MUTYH-Associated Polyposis (MAP) is caused by biallelic pathogenic germline variants in the MUTYH gene. However, individuals harboring monoallelic MUTYH pathogenic variants in the presence of a positive family history have been reported to have a twofold increased risk of colorectal cancer (CRC) and extra colonic cancers. Our aim was to characterize the spectrum of monoallelic and biallelic germline MUTYH pathogenic variants in Latin American patients and to describe their clinical and genetic characteristics. Patients were identified from eight high-risk genetic cancer centers of five Latin American countries. Statistical analysis was performed using the two-sided P test using the Vassarstats statistical tools. Statistical significance was set at a p value ≤ 0.05. Of the 105 unrelated patients with cancer or colorectal polyposis, 84.8% and 15.2% carried pathogenic monoallelic and biallelic MUTYH variants, respectively. The most common pathogenic variants were p.Gly396Asp and p.Tyr179Cys (55% and 23%, respectively). The mean age at first diagnosis was 48.29 years (range 31-71) and 49.90 years (range 27-87) in biallelic and monoallelic MUTYH patients, respectively. CRC was the only cancer diagnosed in patients with biallelic MUTYH pathogenic variants (75%), while breast cancer (46.1%) was more common than CRC (24.7%) in individuals with monoallelic MUTYH pathogenic variants. We reported a high frequency of European founder variants in our diverse population. Some phenotypic differences from current studies were identified, such as a higher breast cancer burden in monoallelic carriers and a complete absence of extra-colon tumors in biallelic patients.

Genetic and epigenetic characteristics of patients with colorectal cancer from Uruguay.

Colorectal cancer (CRC), the 3rd most frequent cancer worldwide, affects both men and women. This pathology arises from the progressive accumulation of genetic and epigenetic alterations. In this study, KRAS, NRAS, PIK3CA, and BRAF gene mutations, mismatch repair (MMR) genes methylation profile, microsatellite instability (MSI) and CpG Island Methylator Phenotype (CIMP) status were assessed. The associations of these molecular features with clinicopathological data were also investigated. A hundred and eight unselected CRC samples and their histological and clinical data, were gathered between 2017 and 2020. The prevalence of KRAS, NRAS and BRAF gene mutations was similar to that described in other populations. 28.7% of tumors were KRAS-mutated, mostly in men, distal location, with a CIMP-negative status. BRAFV600E frequency was 6.5% and associated with MSI (p = 0.048), MLH1-methylated (p < 0.001) and CIMP-High (p < 0.001) status. We also confirmed that BRAFV600E tumors were more prevalent in older women and proximal location. A striking different result was the lack of most common variants in the PIK3CA gene. A complete absence of PIK3CA-mutated tumors in a population has not been previously reported. Among MMR genes, the only with an aberrant methylation pattern was MLH1 gene. Its frequency was 9.25%, lower than previously reported. Methylated tumors were most frequent in patients older than 70 years old and proximal tumor location. Finally, CIMP-High status was mainly observed in moderately differentiated tumors with a rate of 15.7%. Our findings were consistent with previous reports in other populations, but also showed some features unique to our cohort. This study is the first to report the analysis of a large number molecular biomarkers of CRC in Uruguay and one of the few performed in Latin-America.

CYP2D6 genotyping and the clinical impact on outcomes in breast cancer tamoxifen-treated patients.

Aims: To report the distribution of allele frequencies of CYP2D6 gene and to evaluate their influence on the clinical outcomes of a group of breast cancer patients receiving adjuvant tamoxifen treatment from Uruguay. Patients & methods: 199 samples were genotyped through real-time polymerase chain reaction assays. Metabolization profiles were inferred from the genotypes. Correlations were evaluated using Pearson's χ2 test. Results: Phenotype frequencies were 0.65 normal (NM), 0.30 intermediate (IM) and 0.05 poor metabolizers (PM). Similar clinical outcomes between NM and (PM + IM) patient groups (odds ratio = 1.011, 95% CI = 0.2703-3.7826; p = 0.987) were found. Conclusion: CYP2D6 allele frequencies were analyzed for the first time in a cohort from Uruguay. Results did not support any impact of CYP2D6 gene polymorphisms on clinical outcomes.

Assessing Adherence to Adjuvant Hormone Therapy in Breast Cancer Patients in Routine Clinical Practice.

Background: Adjuvant hormone therapy (HT) in patients with hormone receptor-positive breast cancer (BC) increases overall survival (OS). A lack of adherence to adjuvant endocrine therapy is common, 31.0-73.0% of women discontinue endocrine treatment before 5 years. The aim of the study was to assess adherence to HT in routine clinical practice in patients assisted at the Clinical Oncology Department of the Hospital de Clinicas - Universidad de la Republica, Uruguay. Methods: Patients treated with HT for stage 0-III BC between 2017 and 2019 were included. The medication possession (MPR) rate was calculated using pharmacy records, and the Morisky-Green Scale was applied to assess adherence. Adherent patients were those with MPR ≥ 0.80 and who correctly answered the Morisky-Green treatment adherence questionnaire. The association of adherence with polypharmacy, treatment, and patient characteristics was assessed using simple logistic models. The associations between qualitative variables and adherence were assessed using simple logistic regression model or Fisher's exact test. The association between quantitative variables and adherence was assessed using the Student's t-test. The odds ratio (OR) for non-adherence to treatment and its 95% confidence interval were estimated. Results: Totally, 118 patients were included; 65.2% were treated with aromatase inhibitors (AIs), 36.0% presenting polypharmacy. The adherence rate at the end of 2 years was 81.0 %; and it was associated with age (P = 0.03, OR = 0.96 for non-adherence), with adherent and non-adherent patients having a mean age of 65.0 and 60.3 years, respectively; however, adherence was not associated with polypharmacy, territory of origin, marital status, living alone, level of education, occupation, or stage. The adherence profile was similar for both drugs, but homemakers and retired women showed greater adherence to AI. Conclusions: Adherence to HT was assessed in real life, with 19.0% of the patients not adhering to the treatment, despite the known benefit for OS, being a well-tolerated treatment, and being provided free of charge. Older patients were associated with being more adherent. The results show the need of the Pharmacy Service and Department of Clinical Oncology Medical Oncology combining efforts to develop coordinated strategies and interventions to increase adherence, given the impact that this may have on patients' OS.

An updated examination of the perception of barriers for pharmacogenomics implementation and the usefulness of drug/gene pairs in Latin America and the Caribbean.

Pharmacogenomics (PGx) is considered an emergent field in developing countries. Research on PGx in the Latin American and the Caribbean (LAC) region remains scarce, with limited information in some populations. Thus, extrapolations are complicated, especially in mixed populations. In this paper, we reviewed and analyzed pharmacogenomic knowledge among the LAC scientific and clinical community and examined barriers to clinical application. We performed a search for publications and clinical trials in the field worldwide and evaluated the contribution of LAC. Next, we conducted a regional structured survey that evaluated a list of 14 potential barriers to the clinical implementation of biomarkers based on their importance. In addition, a paired list of 54 genes/drugs was analyzed to determine an association between biomarkers and response to genomic medicine. This survey was compared to a previous survey performed in 2014 to assess progress in the region. The search results indicated that Latin American and Caribbean countries have contributed 3.44% of the total publications and 2.45% of the PGx-related clinical trials worldwide thus far. A total of 106 professionals from 17 countries answered the survey. Six major groups of barriers were identified. Despite the region's continuous efforts in the last decade, the primary barrier to PGx implementation in LAC remains the same, the "need for guidelines, processes, and protocols for the clinical application of pharmacogenetics/pharmacogenomics". Cost-effectiveness issues are considered critical factors in the region. Items related to the reluctance of clinicians are currently less relevant. Based on the survey results, the highest ranked (96%-99%) gene/drug pairs perceived as important were CYP2D6/tamoxifen, CYP3A5/tacrolimus, CYP2D6/opioids, DPYD/fluoropyrimidines, TMPT/thiopurines, CYP2D6/tricyclic antidepressants, CYP2C19/tricyclic antidepressants, NUDT15/thiopurines, CYP2B6/efavirenz, and CYP2C19/clopidogrel. In conclusion, although the global contribution of LAC countries remains low in the PGx field, a relevant improvement has been observed in the region. The perception of the usefulness of PGx tests in biomedical community has drastically changed, raising awareness among physicians, which suggests a promising future in the clinical applications of PGx in LAC.

Genetic variants associated with methotrexate-induced mucositis in cancer treatment: A systematic review and meta-analysis.

Methotrexate (MTX), an important chemotherapeutic agent, is often accompanied with mucositis. The occurrence and severity are unpredictable and show large interindividual variability. In this study, we review and meta-analyze previously studied genetic variants in relation to MTX-induced mucositis. We conducted a systematic search in Medline and Embase. We included genetic association studies of MTX-induced mucositis in cancer patients. A meta-analysis was conducted for single nucleotide polymorphisms (SNPs) for which at least two studies found a statistically significant association. A total of 34 SNPs were associated with mucositis in at least one study of the 57 included studies. Two of the seven SNPs included in our meta-analysis were statistically significantly associated with mucositis: MTHFR c.677C > T (recessive, grade ≥3 vs grade 0-2, OR 2.53, 95 %CI [1.48-4.32], False Discovery Rate[FDR]-corrected p-value 0.011) and MTRR c.66A > G (overdominant, grade ≥1 vs grade 0, OR 2.08, 95 %CI [1.16-3.73], FDR-corrected p-value 0.042).

Evaluación de parámetros inflamatorios, trombóticos y variantes genéticas en pacientes con ataque cerebrovascular isquémico que se asisten en un hospital de Uruguay

Introducción: El ataque cerebrovascular es la segunda causa de muerte en adultos en el mundo occidental y una de las principales causas de discapacidad permanente, aumentando su frecuencia con la edad, el 85 % es de tipo isquémico. Objetivos: Analizar parámetros trombofílicos, hipofibrinolíticos y genéticos en pacientes con ataque cerebrovascular isquémico y evaluar la posible asociación de estos con factores de riesgo cardiovascular. Metodología: Se utilizó un cuestionario para evaluar la presencia de factores de riesgo cardiovascular en 114 pacientes incluidos en el estudio con diagnóstico de ataque cerebrovascular isquémico. Proteína C y antitrombina fueron determinados mediante métodos cromogénicos, resistencia a la proteína C activada e inhibidor lúpico mediante métodos coagulométricos y proteína S libre, inhibidor del activador del plasminógeno-1, homocisteína y lipoproteína (a) por métodos inmunoquímicos. Fibrinógeno fue determinado por coagulometría y proteína C reactiva por inmunoturbidimetría, ambos contra un grupo control. Las variantes genéticas factor V Leiden, protrombina G20210A, rs1205 (gen PCR), rs1800779 (gen NOS3) y rs2257073 (gen ASB10) fueron analizadas mediante real-time PCR, comparando los últimos tres con una población de referencia. La alteración de las frecuencias de las variables fue determinada por análisis estadístico chi-cuadrado. Resultados: Tres de los cuatro pacientes jóvenes estudiados presentaron indicadores de trombofilia. El resto de los parámetros alterados fueron homocisteína 30.1% (22.4-39.1), lipoproteína (a) 32.1% (24.1-41.4), inhibidor del activador del plasminógeno-1 36.0% (27.8-45.1), fibrinógeno 12.3% (7.5-19.6) y proteína C reactiva 78.1% (69.6-84.7). Se encontró asociación (p < 0.05) entre ciertos factores de riesgo cardiovascular y los parámetros evaluados como hipertensión/proteína C reactiva, dislipemia/lipoproteína (a), arritmia/lipoproteína (a) y arritmia/fibrinógeno. Para pacientes con ataque cerebrovascular isquémico solo la variante rs1205 mostró una frecuencia más alta del alelo T. Conclusiones: Este estudio revela la importancia de analizar la trombofilia en pacientes jóvenes, especialmente en aquellos sin factores de riesgo cardiovascular, así como el rol de la hipofibrinolisis, inflamación y algunas variantes genéticas en el desarrollo de ataque cerebro vascular isquémico.

Introduction: Stroke is the second cause of death in adults in the Western world and one of the main causes of permanent disability, increasing in frequency with age; 85% are ischemic. Objectives: To analyze thrombophilic, hypofibrinolytic, inflammatory, and genetic parameters in patients with ischemic stroke and evaluate possible associations with vascular risk factors. Methodology: Questionnaires were used to evaluate vascular risk factors in 114 patients included in the study with ischemic stroke diagnosis. Protein C and Antithrombin were determined by chromogenic assays, Activated Protein C Resistance and Lupus Anticoagulant were determined with by coagulometry and Free Protein S, Plasminogen activator inhibitor-1, Homocysteine and Lipoprotein (a) by immunochemistry. Fibrinogen was assayed by coagulometry and C-reactive protein by immunoturbidimetry, both against a control group. Factor V Leiden, Prothrombin G20210A, rs1205 (CRP gene), rs1800779 (NOS3 gene) and rs2257073 (ASB10 gene) genetic variants were analyzed by Real-Time PCR, comparing the last three with a reference population. Alteration frequencies of the variables were determined by chi-square statistical analysis. Results: Three out of four of the young patients studied presented indicators of thrombophilia. The rest of the altered parameters were Homocysteine 30.1% (22.4-39.1), Lipoprotein (a) 32.1% (24.1-41.4), Plasminogen activator inhibitor-1 36.0% (27.8-45.1), Fibrinogen 12.3% (7.5-19.6) and C-reactive protein 78.1% (69.6-84.7). Associations were found (p<0.05) between certain vascular risk factors and parameters evaluated, namely hypertension/C-reactive protein, dyslipidemia/lipoprotein (a), arrhythmia/lipoprotein (a) and arrhythmia/fibrinogen. For ischemic stroke patients only the genetic variant rs1205 showed higher frequency of the T allele. Conclusions: This study reveals the importance of analyzing thrombophilia in young patients, especially those without vascular risk factors, as well as the role of hypofibrinolysis, inflammation and some genetic variants in the development of ischemic stroke.

Introdução: O AVC é a segunda causa de morte em adultos no mundo ocidental e uma das principais causas de incapacidade permanente, aumentando de frequência com a idade; 85% são isquémicos. Metas: Analisar os parâmetros trombofílicos, hipofibrinolíticos e genéticos em pacientes com acidente vascular cerebral isquêmico e avaliar a possível associação com fatores de risco cardiovascular. Metodologia: Um questionário foi utilizado para avaliar a presença de fatores de risco cardiovascular em 114 pacientes incluídos no estudo com diagnóstico de acidente vascular cerebral isquêmico. Proteína C e antitrombina foram determinadas por métodos cromogênicos, resistência à proteína C ativada e inibidor de lúpus por métodos coagulométricos e proteína S livre, inibidor do ativador do plasminogênio-1, homocisteína e lipoproteína (a) por métodos imunoquímicos. O fibrinogênio foi determinado por coagulometria e a proteína C-reativa por imunoturbidimetria, ambos contra um grupo controle. As variantes genéticas fator V Leiden, protrombina G20210A, rs1205 (gene PCR), rs1800779 (gene NOS3) e rs2257073 (gene ASB10) foram analisadas por PCR em tempo real, comparando as três últimas com uma população de referência. As frequências de alteração das variáveis ​​foram determinadas pela análise estatística qui-quadrado. Resultados: Três dos quatro pacientes jovens estudados apresentaram indicadores de trombofilia. O resto dos parâmetros alterados foram homocisteína 30,1% (22,4-39,1), lipoproteína (a) 32,1% (24,1-41,4), inibidor do ativador de plasminogênio-1 36,0% (27,8-45,1), fibrinogênio 12,3% (7,5-19,6) e proteína C reativa 78,1% (69,6-84,7). Foi encontrada associação (p<0,05) entre alguns fatores de risco cardiovascular e os parâmetros avaliados como hipertensão/proteína C reativa, dislipidemia/lipoproteína (a), arritmia/lipoproteína (a) e arritmia/fibrinogênio. Para pacientes com acidente vascular cerebral isquêmico apenas a variante rs1205 apresentou maior frequência do alelo T. Conclusões: Este estudo revela a importância de analisar a trombofilia em pacientes jovens, especialmente aqueles sem fatores de risco cardiovascular, bem como o papel da hipofibrinólise, inflamação e algumas variantes genéticas no desenvolvimento do acidente vascular cerebral isquêmico.

Aggressive mutation in a familial adenomatous polyposis syndrome family: when phenotype guides clinical surveillance.

Familial adenomatous polyposis (FAP) is an autosomal dominant genetic condition, caused by mutations in the adenomatous polyposis coli (APC) tumor suppressor gene. Desmoid tumors (DTs) are seen in 15% to 20% of FAP patients. Specific location of mutation serves as a guide to predict colonic and extra colonic manifestations and their aggressiveness. A severe FAP-phenotypic family was registered in a genetic counselling high-risk Uruguayan hereditary cancer clinic. Proband's DNA was analysed by NGS, detecting a pathogenic mutation in APC gene. All willing family members were counselled and encouraged to be tested. Here we report a kindred formed by 16 individuals with a very severe FAP phenotype. A two-base deletion mutation: c.4393_4394delAG in APC gene and a consequent premature stop codon was detected. DTs were diagnosed in 6 individuals, ranging from 2 to 25 years of age. The causes of death were diverse: gastric cancer, rectal cancer and desmoid tumor. The already described genotype-phenotype correlation has proved its worth in this family, as clinical features reflect the mutation location at 3' end of APC gene. The inheritable and lethal nature of the disease needs a tailored follow up approach in order to reduce mortality, optimize local tumor control, and preserve patients' quality of life.

Methotrexate pharmacogenetics in Uruguayan adults with hematological malignant diseases.

BACKGROUND: Individual variability is among the causes of toxicity and interruption of treatment in acute lymphoblastic leukemia (ALL) and severe non-Hodgkin lymphoma (NHL) patients under protocols including Methotrexate (MTX): 2,4-diamino-N10-methyl propyl-glutamic acid. METHODS: 41 Uruguayan patients were recruited. Gene polymorphisms involved in MTX pathway were analyzed and their association with treatment toxicities and outcome was evaluated. RESULTS: Genotype distribution and allele frequency were determined for SLC19A1 G80A, MTHFR C677T and A1298C, TYMS 28bp copy number variation, SLCO1B1 T521C, DHFR C-1610G/T, DHFR C-680A, DHFR A-317G and DHFR 19bp indel. Multivariate analysis showed that DHFR-1610G/T (OR=0.107, p=0.018) and MTHFR677T alleles (OR=0.12, p=0.026) had a strong protective effect against hematologic toxicity, while DHFR-1610CC genotype increased this toxicity (OR=9, p=0.045). No more associations were found. CONCLUSIONS: The associations found between gene polymorphisms and toxicities in this small cohort are encouraging for a more extensive research to gain a better dose individualization in adult ALL and NHL patients. Besides, genotype distribution showed to be different from other populations, reinforcing the idea that genotype data from other populations should not be extrapolated to ours.

Tamizaje para cáncer de mama con resonancia magnética en mujeres portadoras de mutaciones BRCA y no-BRCA / Magnetic resonance imaging breast cancer screening in women who are carriers of BRCA and non-BRCA gene mutations / Rastreamento de câncer de mama com ressonância magnética em mulheres com mutações BRCA e não BRCA

Introducción: la predisposición hereditaria causada por mutaciones patogénicas de la línea germinal (MPG) explica hasta el 10% de los cánceres de mama. Para reducir su impacto en mujeres mutadas se han propuesto diferentes estrategias, tales como las cirugías reductoras de riesgo o el screening con resonancia magnética (RM) de mamas. Métodos: en este estudio observacional retrospectivo se analizaron los registros de mujeres portadoras de MPG para evaluar las diferentes acciones tomadas luego del test genético. A las pacientes no mastectomizadas se les recomendó ingresar a un programa anual de cribado con RM y se evaluó el porcentaje de adherencia al plan, el número de biopsias efectuadas y el número de cánceres de mama detectados. Resultados: se incluyeron 134 mujeres con MPG, con una distribución en tercios iguales de los genes BRCA1, BRCA2 y genes no-BRCA. Entre las mutadas con indicación de seguimiento, 64% ingresaron al programa de cribado con RM. Las razones que llevaron a las mujeres a no ingresar al programa de seguimiento fueron: la oposición del médico tratante (53%), oposición de la paciente (38%), y falta de recursos (9%). Se realizaron seis biopsias por hallazgos en la RM entre las cuales se detectó un cáncer de mama. La incidencia de cáncer fue de 11 cada 1.000 mujeres-años de riesgo. Conclusiones: nuestro programa de seguimiento con RM de pacientes mutadas logró captar un porcentaje alto de candidatas. Una proporción significativa de las mujeres no ingresó debido la desaprobación del médico tratante o de la propia paciente. La evidencia obtenida revela una necesidad imperiosa de reforzar los programas educativos que destaquen la importancia del seguimiento con RM de las pacientes de alto riesgo en nuestro país.

Summary: Introduction: genetic propensity caused by germline pathogenic mutations explain up to 10% of breast cancer cases. Different strategies have been proposed to reduce its impact on women who are carriers of mutations, such as risk-reducing surgeries or breast magnetic resonance screening. Method: observational, retrospective study analyzing the medical records of women who are carriers of germline pathogenic mutations to assess the different measures taken after the genetic test. Non-mastectomized patients were advised to join an annual MRI screening program and the percentage of adherence to plan was evaluated, along with biopsies performed and the number of breast cancer cases detected. Results: 134 women carriers of germline pathogenic mutations were included in the study, with equal distributions in thirds for BRCA1, BRCA2 and non-BRCA genes. 64% of carriers of mutations who were subject to follow-up checkups joined the RMI screening program. The reasons why women failed to join the follow-up program were: the treating physician objected to the program (53%), the patients opposed to program (38%) and lack of resources (9%). Six biopsies were performed as a consequence of findings in the RMI, and one case of breast cancer was detected. Cancer incidence was 11 out of 1000 women - risk years. Conclusions: our RMI follow-up program for women who are carriers of mutations managed to attract a high percentage of candidates. A significant amount of women failed to join the program because of their treating physician's or their own disapproval. Evidence obtained reveals the dramatic need to reinforce educational programs that emphasize on the importance of RMI follow-up of high risk patients in our country.

Introdução: a predisposição hereditária causada por mutações germinativas patogênicas (GMP) explica até 10% dos cânceres de mama. Para reduzir seu impacto em mulheres com mutações, diferentes estratégias têm sido propostas, como cirurgias de redução de risco ou ressonância magnética (RM) das mamas. Métodos: neste estudo observacional retrospectivo, os registros de mulheres portadoras de MPG foram analisados para avaliar as diferentes ações tomadas após o teste genético. Pacientes não mastectomizadas foram recomendadas a entrar em um programa anual de triagem por ressonância magnética e foram avaliados o percentual de adesão ao plano, o número de biópsias realizadas e o número de cânceres de mama detectados. Resultados: foram incluídas 134 mulheres com MPG, com uma distribuição de terços iguais dos genes BRCA1, BRCA2 e não-BRCA. Entre as mulheres com mutações com indicação de acompanhamento, 64% entraram no programa de triagem por ressonância magnética. Os motivos que levaram as mulheres a não ingressarem ao programa de acompanhamento foram: oposição do médico assistente (53%), oposição da paciente (38%) e falta de recursos (9%). Seis biópsias foram realizadas devido a achados de ressonância magnética, entre os quais foi detectado um câncer de mama. A incidência de câncer foi de 11 por 1.000 mulheres-ano de risco. Conclusões: nosso programa de acompanhamento de ressonância magnética para pacientes com mutação conseguiu capturar uma alta porcentagem de candidatas. Uma proporção significativa de mulheres não entrou devido à falta de aprovação do médico assistente ou da própria paciente. As evidências obtidas revelam a necessidade urgente de reforçar programas educacionais que destaquem a importância do acompanhamento por RM de pacientes de alto risco no Uruguai.

Evaluation of a Labelled Bacteriophage with 99mTc as a Potential Agent for Infection Diagnosis.

BACKGROUND AND OBJECTIVE: The design of target-specific molecular imaging probes to determine infection sites are mainly based on the biochemistry of the inflammatory response that may lead to an ideal agent for infection imaging. Infectious diseases timely and specifically diagnosed can be clinically challenging but essential for the patient's recovery. Laboratory tests can detect the responsible microorganism but cannot discriminate between sterile inflammatory disease and truly infectious disease. On the other hand, scintigraphic images, can pinpoint the infection in the body. METHODS: Bacteriophages (phages) are viruses that infect specific bacterial strains. Given the composition of the protein capsid, they could be used as radiopharmaceuticals to diagnose bacterial infection. In this case, PP7 phage was labelled and evaluated as a specific tracer for Pseudomonas aeruginosa infections. 99mTc-Phage synthesis used HYNIC as a bifunctional agent. Physicochemical evaluation included studies such as stability in time, ligand exchange, lipophilicity and bacterial binding assay. Three groups of animals namely; healthy, infected with Pseudomonas aeruginosa and induced sterile inflammation were used to conduct biological evaluation Results: The radiolabelling process required size exclusion purification of the 99mTc-Phage, which was obtained with a radiochemical purity higher than 90%, during 18 hours post labelling. The collective accumulation in the stomach, small intestine and large intestine and thyroid of 99mTc-Phage was negligible, indicating no in vivo reoxidation. The complex presented urinary elimination. Target/ non-target ratio (T/NT) was determined both for sterile inflammation and for infection. Values were 2.5 ± 0.4 and 4.2 ± 0.3 respectively. These values indicate significant differences between sterile inflammation and infection by Pseudomonas aeruginosa (p<0.05 unpaired two sided t-test). CONCLUSION: Targeted biodistribution profile and good T/NT ratios, indicate that this complex presents enough specificity to discriminate between infection caused by Pseudomonas aeruginosa and sterile inflammation.

In vitro and in silico analysis of the Aspergillus nidulans DNA-CreA repressor interactions.

The CreA protein mediates carbon catabolite repression in the fungus Aspergillus nidulans. Its DNA-binding domain belongs to the Cys2-His2 class, binding specifically to a 5' SYGGRG 3' nucleotide sequence. EMSA experiments showed that the CreA(G27D) mutation resulted in a 30-fold increase of the Kdiss, and footprinting revealed a altered pattern of protein/DNA contacts. We modeled the CreA and the CreA(G27D) complexes in silico. A 15 ns molecular dynamics simulation of the solvated CreA(G27D) and CreA models was carried out using the MOE 2007.09 suite and the Amber99 force field. We have focused our analysis in residues Arg14, Glu16, His17, and Arg20 and Arg44, Asp46, and Arg50, previously, shown to be responsible for the specific contacts of the two Zn fingers. The electrostatic and the total potential energies showed the CreA(G27D) mutation to decrease the affinity of the complex, in agreement with the Kdiss's values. The in silico approach highlighted the role of the inter-finger linker. We identified several differential structural characteristics of the CreA and CreA(G27D)/DNA complexes and observed that the latter resulted in a lower dynamic flexibility of the complex.