Risk-reducing hysterectomy and bilateral salpingo-oophorectomy in female heterozygotes of pathogenic mismatch repair variants: a Prospective Lynch Syndrome Database report.

PURPOSE: To determine impact of risk-reducing hysterectomy and bilateral salpingo-oophorectomy (BSO) on gynecological cancer incidence and death in heterozygotes of pathogenic MMR (path_MMR) variants. METHODS: The Prospective Lynch Syndrome Database was used to investigate the effects of gynecological risk-reducing surgery (RRS) at different ages. RESULTS: Risk-reducing hysterectomy at 25 years of age prevents endometrial cancer before 50 years in 15%, 18%, 13%, and 0% of path_MLH1, path_MSH2, path_MSH6, and path_PMS2 heterozygotes and death in 2%, 2%, 1%, and 0%, respectively. Risk-reducing BSO at 25 years of age prevents ovarian cancer before 50 years in 6%, 11%, 2%, and 0% and death in 1%, 2%, 0%, and 0%, respectively. Risk-reducing hysterectomy at 40 years prevents endometrial cancer by 50 years in 13%, 16%, 11%, and 0% and death in 1%, 2%, 1%, and 0%, respectively. BSO at 40 years prevents ovarian cancer before 50 years in 4%, 8%, 0%, and 0%, and death in 1%, 1%, 0%, and 0%, respectively. CONCLUSION: Little benefit is gained by performing RRS before 40 years of age and premenopausal BSO in path_MSH6 and path_PMS2 heterozygotes has no measurable benefit for mortality. These findings may aid decision making for women with LS who are considering RRS.

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.

Tamoxifen acts on Trypanosoma cruzi sphingolipid pathway triggering an apoptotic death process.

This study shows the effects of tamoxifen, a known estrogen receptor antagonist used in the treatment of breast cancer, on the sphingolipid pathway of Trypanosoma cruzi, searching for potential chemotherapeutic targets. A dose-dependent epimastigote growth inhibition at increasing concentration of tamoxifen was determined. In blood trypomastigotes, treatment with 10 µM showed 90% lysis, while 86% inhibition of intracellular amastigote development was obtained using 50 µM. Lipid extracts from treated and non-treated metabolically labelled epimastigotes evidenced by thin layer chromatography different levels of sphingolipids and MALDI-TOF mass spectrometry analysis assured the identity of the labelled species. Comparison by HPLC-ESI mass spectrometry of lipids, notably exhibited a dramatic increase in the level of ceramide in tamoxifen-treated parasites and a restrained increase of ceramide-1P and sphingosine, indicating that the drug is acting on the enzymes involved in the final breakdown of ceramide. The ultrastructural analysis of treated parasites revealed characteristic morphology of cells undergoing an apoptotic-like death process. Flow cytometry confirmed cell death by an apoptotic-like machinery indicating that tamoxifen triggers this process by acting on the parasitic sphingolipid pathway.

Effect of tamoxifen on the sphingolipid biosynthetic pathway in the different intraerythrocytic stages of the apicomplexa Plasmodium falciparum.

Parasites of the genus Plasmodium responsible for Malaria are obligate intracellular pathogens residing in mammalian red blood cells, hepatocytes, or mosquito midgut epithelial cells. Regarding that detailed knowledge on the sphingolipid biosynthetic pathway of the apicomplexan protozoan parasites is scarce, different stages of Plasmodium falciparum were treated with tamoxifen in order to evaluate the effects of this drug on the glycosphingolipid biosynthesis. Thin layer chromatography, High performance reverse phase chromatography and UV-MALDI-TOF mass spectrometry were the tools used for the analysis. In the ring forms, the increase of NBD-phosphatidyl inositol biosynthesis was notorious but differences at NBD-GlcCer levels were undetectable. In trophozoite forms, an abrupt decrease of NBD-acylated GlcDHCer and NBD-GlcDHCer in addition to an increase of NBD-PC biosynthesis was observed. On the contrary, in schizonts, tamoxifen seems not to be producing substantial changes in lipid biosynthesis. Our findings indicate that in this parasite, tamoxifen is exerting an inhibitory action on Glucosylceramidesynthase and sphingomyelin synthase levels. Moreover, regarding that Plasmodium does not biosynthesize inositolphosphoceramides, the accumulation of phosphatidylinositol should indicate an inhibitory action on glycosylinositol phospholipid synthesis.

A survey of the clinicopathological and molecular characteristics of patients with suspected Lynch syndrome in Latin America.

BACKGROUND: Genetic counselling and testing for Lynch syndrome (LS) have recently been introduced in several Latin America countries. We aimed to characterize the clinical, molecular and mismatch repair (MMR) variants spectrum of patients with suspected LS in Latin America. METHODS: Eleven LS hereditary cancer registries and 34 published LS databases were used to identify unrelated families that fulfilled the Amsterdam II (AMSII) criteria and/or the Bethesda guidelines or suggestive of a dominant colorectal (CRC) inheritance syndrome. RESULTS: We performed a thorough investigation of 15 countries and identified 6 countries where germline genetic testing for LS is available and 3 countries where tumor testing is used in the LS diagnosis. The spectrum of pathogenic MMR variants included MLH1 up to 54%, MSH2 up to 43%, MSH6 up to 10%, PMS2 up to 3% and EPCAM up to 0.8%. The Latin America MMR spectrum is broad with a total of 220 different variants which 80% were private and 20% were recurrent. Frequent regions included exons 11 of MLH1 (15%), exon 3 and 7 of MSH2 (17 and 15%, respectively), exon 4 of MSH6 (65%), exons 11 and 13 of PMS2 (31% and 23%, respectively). Sixteen international founder variants in MLH1, MSH2 and MSH6 were identified and 41 (19%) variants have not previously been reported, thus representing novel genetic variants in the MMR genes. The AMSII criteria was the most used clinical criteria to identify pathogenic MMR carriers although microsatellite instability, immunohistochemistry and family history are still the primary methods in several countries where no genetic testing for LS is available yet. CONCLUSION: The Latin America LS pathogenic MMR variants spectrum included new variants, frequently altered genetic regions and potential founder effects, emphasizing the relevance implementing Lynch syndrome genetic testing and counseling in all of Latin America countries.

[Founder mutation in Lynch syndrome]. / Mutación fundadora en síndrome de Lynch tipo II.

Lynch syndrome is the most frequent syndrome in hereditary colorectal cancer, a family-specific deleterious mutations in genes encoding DNA reparation proteins: MLH1 (mutL homolog 1), MSH2, MSH6 (mutS homolog 2 y 6, respectively), PMS2 (PMS1 homolog 2, mismatch repair system component) y MUTYH (mutY DNA glycosylase). The c.2252_2253delAA, p.Lys751Serfs*3 mutation in MLH1 gene segregates with a haplotype reported in the northern region of Italy and whose origin was attributed to a founder effect. This mutation co-segregates with typical characteristics of Lynch syndrome, including early age at onset and multiple primary tumors in the same individual, a high frequency of pancreatic cancer, high microsatellite instability and lack of PMS2 expression. This report describes a mutation in an Argentinian patient with endometrioid adenocarcinoma of uterus. Her first-degree relatives had a history of colon cancer diagnosed before 50 years, fulfilling the Amsterdam Criteria I and Lynch syndrome II. The high pathogenicity associated to this mutation makes necessary the study of all members from families with hereditary cancer, allowing pre-symptomatic genetic diagnosis, early assessment and the instauration of preventive treatments.

The colorectal cancer-associated faecal microbiome of developing countries resembles that of developed countries.

BACKGROUND: The incidence of colorectal cancer (CRC) is increasing in developing countries, yet limited research on the CRC- associated microbiota has been conducted in these areas, in part due to scarce resources, facilities, and the difficulty of fresh or frozen stool storage/transport. Here, we aimed (1) to establish a broad representation of diverse developing countries (Argentina, Chile, India, and Vietnam); (2) to validate a 'resource-light' sample-collection protocol translatable in these settings using guaiac faecal occult blood test (gFOBT) cards stored and, importantly, shipped internationally at room temperature; (3) to perform initial profiling of the collective CRC-associated microbiome of these developing countries; and (4) to compare this quantitatively with established CRC biomarkers from developed countries. METHODS: We assessed the effect of international storage and transport at room temperature by replicating gFOBT from five UK volunteers, storing two in the UK, and sending replicates to institutes in the four countries. Next, to determine the effect of prolonged UK storage, DNA extraction replicates for a subset of samples were performed up to 252 days apart. To profile the CRC-associated microbiome of developing countries, gFOBT were collected from 41 treatment-naïve CRC patients and 40 non-CRC controls from across the four institutes, and V4 16S rRNA gene sequencing was performed. Finally, we constructed a random forest (RF) model that was trained and tested against existing datasets from developed countries. RESULTS: The microbiome was stably assayed when samples were stored/transported at room temperature and after prolonged UK storage. Large-scale microbiome structure was separated by country and continent, with a smaller effect from CRC. Importantly, the RF model performed similarly to models trained using external datasets and identified similar taxa of importance (Parvimonas, Peptostreptococcus, Fusobacterium, Alistipes, and Escherichia). CONCLUSIONS: This study demonstrates that gFOBT, stored and transported at room temperature, represents a suitable method of faecal sample collection for amplicon-based microbiome biomarkers in developing countries and suggests a CRC-faecal microbiome association that is consistent between developed and developing countries.

Maternal ancestry and hematological cancer risk: case-control study in an Argentinean population.

Aim: We investigated the role of maternal ancestry in neoplastic hematological malignancies (HMs) risk in a population from Central Argentina. Materials & methods: We analyzed 125 cases with HMs and 310 controls from a public hospital, and a set of 202 colorectal, breast, lung, and hematologic cancer patients from a private hospital. Results: A decreased risk for HMs was associated with the Native American haplogroup B2 (odds ratio = 0.49; 95% CI: 0.25-0.92; p = 0.02). The sub-Saharan African parahaplogroup L was associated with higher susceptibility for disease (odds ratio = 3.10; 95% CI: 1.04-9.31; p = 0.043). Although the mean ancestral proportions in the total studied population was as published (61.7% Native American, 34.6% European and 3.7% African), an unequal distribution was observed between hospitals. Conclusion: We confirmed the tri-hybrid nature of the Argentinean population, with proportions varying within the country. Our finding supports the notion that associated haplogroup is population and cancer specific.

Uptake of hysterectomy and bilateral salpingo-oophorectomy in carriers of pathogenic mismatch repair variants: a Prospective Lynch Syndrome Database report.

PURPOSE: This study aimed to report the uptake of hysterectomy and/or bilateral salpingo-oophorectomy (BSO) to prevent gynaecological cancers (risk-reducing surgery [RRS]) in carriers of pathogenic MMR (path_MMR) variants. METHODS: The Prospective Lynch Syndrome Database (PLSD) was used to investigate RRS by a cross-sectional study in 2292 female path_MMR carriers aged 30-69 years. RESULTS: Overall, 144, 79, and 517 carriers underwent risk-reducing hysterectomy, BSO, or both combined, respectively. Two-thirds of procedures before 50 years of age were combined hysterectomy and BSO, and 81% of all procedures included BSO. Risk-reducing hysterectomy was performed before age 50 years in 28%, 25%, 15%, and 9%, and BSO in 26%, 25%, 14% and 13% of path_MLH1, path_MSH2, path_MSH6, and path_PMS2 carriers, respectively. Before 50 years of age, 107 of 188 (57%) BSO and 126 of 204 (62%) hysterectomies were performed in women without any prior cancer, and only 5% (20/392) were performed simultaneously with colorectal cancer (CRC) surgery. CONCLUSION: Uptake of RRS before 50 years of age was low, and RRS was rarely undertaken in association with surgical treatment of CRC. Uptake of RRS aligned poorly with gene- and age-associated risk estimates for endometrial or ovarian cancer that were published recently from PLSD and did not correspond well with current clinical guidelines. The reasons should be clarified. Decision-making on opting for or against RRS and its timing should be better aligned with predicted risk and mortality for endometrial and ovarian cancer in Lynch syndrome to improve outcomes.

MLH1 intronic variants mapping to + 5 position of splice donor sites lead to deleterious effects on RNA splicing.

Germline pathogenic variants in the DNA mismatch repair genes (MMR): MLH1, MSH2, MSH6, and PMS2, are causative of Lynch syndrome (LS). However, many of the variants mapping outside the invariant splice site positions (IVS ± 1, IVS ± 2) are classified as variants of unknown significance (VUS). Three such variants (MLH1 c.588+5G>C, c.588+5G>T and c.677+5G>A) were identified in 8 unrelated LS families from Argentina, Brazil and Chile. Herein, we collected clinical information on these families and performed segregation analysis and RNA splicing studies to assess the implication of these VUS in LS etiology. Pedigrees showed a clear pattern of variant co-segregation with colorectal cancer and/or other LS-associated malignancies. Tumors presented deficient expression of MLH1-PMS2 proteins in 7/7 of the LS families, and MSI-high status in 3/3 cases. Moreover, RNA analyses revealed that c.588+5G>C and c.588+5G>T induce skipping of exon 7 whereas c.677+5G>A causes skipping of exon 8. In sum, we report that the combined clinical findings in the families and the molecular studies provided the evidences needed to demonstrate that the three MLH1 variants are causative of LS and to classify c.588+5G>C and c.677+5G>A as class 5 (pathogenic), and c.588+5G>T as class 4 (likely-pathogenic). Our findings underline the importance of performing clinical and family analyses, as well as RNA splicing assays in order to determine the clinical significance of intronic variants, and contribute to the genetic counseling and clinical management of patients and their relatives.

Risk-Reducing Gynecological Surgery in Lynch Syndrome: Results of an International Survey from the Prospective Lynch Syndrome Database.

PURPOSE: To survey risk-reducing hysterectomy and bilateral salpingo-oophorectomy (BSO) practice and advice regarding hormone replacement therapy (HRT) in women with Lynch syndrome. METHODS: We conducted a survey in 31 contributing centers from the Prospective Lynch Syndrome Database (PLSD), which incorporates 18 countries worldwide. The survey covered local policies for risk-reducing hysterectomy and BSO in Lynch syndrome, the timing when these measures are offered, the involvement of stakeholders and advice regarding HRT. RESULTS: Risk-reducing hysterectomy and BSO are offered to path_MLH1 and path_MSH2 carriers in 20/21 (95%) contributing centers, to path_MSH6 carriers in 19/21 (91%) and to path_PMS2 carriers in 14/21 (67%). Regarding the involvement of stakeholders, there is global agreement (~90%) that risk-reducing surgery should be offered to women, and that this discussion may involve gynecologists, genetic counselors and/or medical geneticists. Prescription of estrogen-only HRT is offered by 15/21 (71%) centers to women of variable age range (35-55 years). CONCLUSIONS: Most centers offer risk-reducing gynecological surgery to carriers of path_MLH1, path_MSH2 and path_MSH6 variants but less so for path_PMS2 carriers. There is wide variation in how, when and to whom this is offered. The Manchester International Consensus Group developed recommendations to harmonize clinical practice across centers, but there is a clear need for more research.

A snapshot of current genetic testing practice in Lynch syndrome: The results of a representative survey of 33 Latin American existing centres/registries.

We aimed to assess the current genetics practice to manage patients with Lynch syndrome (LS) across Latin America. A Latin American LS survey was sent out to 52 centres/registries, comprising a total of 12 countries from the region. Overall, 33 centres completed the survey, of which the oldest LS registry was established in 1992 in Sao Paulo (Brazil), and the youngest this year in San Jose (Costa Rica). In total, 87% (26/30) of the participating centres/registries belonging to the nine countries are performing genetic testing. Overall, 1352 suspected families were sequenced. Pathogenic variants were identified in 34% of the families, with slightly differing distribution of variants between females and males. Path_MLH1 variants were identified in 39% of females and 50% of males (p = 0.023), while path_MSH2 were identified in 37% of females and males, followed by path_PMS2 in 11% of females and 8% of males, path_MSH6 in 13% of females and 3% of males (p < 0.001) and path_EPCAM in 0.3% of females and 2% of males. In Latin America, 9 of 12 (75%) participating countries had implemented healthcare for LS. LS screening is inconsistently applied within Latin America healthcare systems because of structural differences in the healthcare systems between the countries.

Universal determination of microsatellite instability using BAT26 as a single marker in an Argentine colorectal cancer cohort.

Microsatellite instability (MSI) is a hallmark tool for Lynch syndrome (LS) screening and a prognostic marker for sporadic colorectal cancer (CRC). In regions with limited resources and scarce CRC molecular characterization as South America, the implementation of universal MSI screening is under debate for both its purposes. We sought to estimate the frequency of BAT26 in colorectal adenocarcinomas and to determine associated clinical and histological features. Consecutive patients from a CRC registry were included. BAT26 determination was performed in all cases; if instability was found, immunohistochemistry (IHC) and BRAF mutation analyses were done, as appropriate. Differences were assessed by chi-squared or Fisher's exact test, or by T test or Mann-Whitney. Multiple logistic regression was used to identify factors independently associated with BAT26-unstable tumors. We included 155 patients; mean age was 65.6 (SD 14.4) and 56.1% were male. The frequency of BAT26-unstable tumors was 22% (95% CI 15.7-29.3). Factors independently associated with BAT26-unstable tumors were right colon localization (OR 3.4, 95% CI 1.3-8.7), histological MSI features (OR 5.1, 95% CI 1.9-13.6) and Amsterdam criteria (OR 23.2, 95% CI 1.9-286.7). IHC was altered in 85.3% BAT26-unstable tumors and 70.6% lacked MLH1 expression; 47.8% of these harbored BRAF V600E mutation. We provide evidence to link the frequency of BAT26 to an increased diagnostic yield (up to 1.4-folds) of suspected LS cases in comparison to the revised Bethesda guidelines alone. In regions with limited resources, clinical and histological features associated with BAT26-unstable status could be useful to direct MSI screening in sporadic CRCs and may help guide clinical care and future research.

Investigación traslacional en microbioma (InTraMic): un área de interés común y creciente en el IMTIB, Hospital Italiano e Instituto Universitario / Translational research in microbiome (InTraMic): an area of common and growing interest at IMTIB, Hospital Italiano and Instituto Universitario

Se estima que aproximadamente 100 trillones de microorganismos (incluidos bacterias, virus y hongos) residen en el intestino humano adulto y que el total del material genético del microbioma es 100 veces superior al del genoma humano. Esta comunidad, conocida como microbioma se adquiere al momento del nacimiento a través de la flora comensal de la piel, vagina y heces de la madre y se mantiene relativamente estable a partir de los dos años desempeñando un papel crítico tanto en el estado de salud como en la enfermedad. El desarrollo de nuevas tecnologías, como los secuenciadores de próxima generación (NGS), permiten actualmente realizar un estudio mucho más preciso de ella que en décadas pasadas cuando se limitaba a su cultivo. Si bien esto ha llevado a un crecimiento exponencial en las publicaciones, los datos sobre las poblaciones Latinoamérica son casi inexistentes. La investigación traslacional en microbioma (InTraMic) es una de las líneas que se desarrollan en el Instituto de Medicina Traslacional e Ingeniería Biomédica (IMTIB). Esta se inició en 2018 con la línea de cáncer colorrectal (CCR) en una colaboración con el Colorectal Cancer Research Group del Leeds Institute of Medical Research en el proyecto Large bowel microbiome disease network: Creation of a proof of principle exemplar in colorectal cancer across three continents. A fines de 2019 se cumplió el objetivo de comprobar la factibilidad de la recolección, envío y análisis de muestras de MBF en 5 continentes, incluyendo muestras provenientes de la Argentina, Chile, India y Vietnam. Luego de haber participado de capacitaciones en Inglaterra, se ha cumplido con el objetivo de la etapa piloto, logrando efectivizar la recolección, envío y análisis metagenómico a partir de la secuenciación de la región V4 del ARNr 16S. En 2019, la línea de enfermedad de hígado graso no alcohólico se sumó a la InTraMic iniciando una caracterización piloto en el marco de una colaboración con el laboratorio Novartis. Los resultados de ese estudio, así como el de cáncer colorrectal, están siendo enviados a publicación. En 2020, con la incorporación de la línea de trasplante alogénico de células progenitoras hematopoyéticas, fue presentado un proyecto para un subsidio del CONICET que ha superado la primera etapa de evaluación. En el presente artículo se brinda una actualización sobre la caracterización taxonómica de microbioma y se describen las líneas de investigación en curso. (AU)

It is estimated that approximately 100 trillion microorganisms (including bacteria, viruses, and fungi) reside in the adult human intestine, and that the total genetic material of the microbiome is 100 times greater than that of the human genome. This community, known as the microbiome, is acquired at birth through the commensal flora of the mother's skin, vagina, and feces and remains relatively stable after two years, playing a critical role in both the state of health and in disease. The development of new technologies, such as next-generation sequencers (NGS), currently allow for a much more precise study of it than in past decades when it was limited to cultivation. Although this has led to exponential growth in publications, data on Latin American populations is almost non-existent. Translational research in microbiome (InTraMic) is one of the lines developed at the Instituto de Medicina Traslacional e Ingeniería Biomédica (IMTIB). This started in 2018 with the Colorectal Cancer Line (CRC) in a collaboration with the Colorectal Cancer Research Group of the Leeds Institute of Medical Research in the project "Large bowel microbiome disease network: Creation of a proof of principle exemplar in colorectal cancer across three continents". At the end of 2019, the objective of verifying the feasibility of collecting, sending and analyzing MBF samples on 5 continents, including samples from Argentina, Chile, India and Vietnam, was met. After having participated in training in England, the objective of the pilot stage has been met, achieving the collection, delivery and metagenomic analysis from the sequencing of the V4 region of the 16S rRNA. In 2019, the non-alcoholic fatty liver disease line joined InTraMic, initiating a pilot characterization in the framework of a collaboration with the Novartis laboratory. The results of that study, as well as that of colorectal cancer, are being published. In 2020, with the incorporation of the allogeneic hematopoietic stem cell transplantation line, a project was presented for a grant from the CONICET that has passed the first stage of evaluation. This article provides an update on the taxonomic characterization of the microbiome and describes the lines of ongoing research. (AU)

Síndrome de Lynch: impacto de la caracterización de familias en base a estudios genéticos / Lynch syndrome: impact of the characterization of families based on genetic studies

El objetivo de este trabajo fue caracterizar demográfica y molecularmente las familias con diagnóstico de síndrome de Lynch en base a estudios genéticos. Se utilizó la base prospectiva del Registro de Epidemiología Molecular de Cáncer Colorrectal (REM-CCR) del Hospital Italiano de Buenos Aires (Clinical trials.gov NCT02781337). El criterio de inclusión fue que tuvieran hecho un estudio genético entre 1996 y 2017 (secuenciación y/o determinación de grandes rearreglos de al menos un gen reparador de error de apareamiento). Se analizaron 50 familias con los criterios de Amsterdam. En 23 (46%) se identificaron variantes patogénicas (n=19) y probablemente patogénicas (n=2). El 28.6% de las variantes patogénicas fueron originalmente descritas en esta serie, entre ellas la variante c.1911del en el exón 12 de MSH2 identificada en una familia con agregación de cáncer de mama. Fue identificada una mutación fundadora de Piamonte, Italia (c.2252_2253del). Los genes afectados incluyeron MSH2 (13 variantes) MLH1 (9 variantes) y PMS2 (1 variante). La tasa de detección de mutaciones fue del 46%. Entre las familias con mutación identificada (n=23), se detectó una edad mediana de inicio del cáncer menor (46 vs. 50 años, p=0.02) y mayor incidencia de tumores extra-colorrectales (90.5% vs. 45.8%, p <0.01), que las 27 sin mutaciones. La implementación de estudios genéticos permitió caracterizar variables demográficas en base a la identificación de mutaciones germinales asociadas al síndrome de Lynch, identificándose dos grupos diferenciados por la edad de afectación y la incidencia de tumores extracolónicos (AU)

The aim of this study was to characterize demographically and molecularly families diagnosed with Lynch syndrome based on genetic studies. Families with a genetic study performed between 1996 and 2017 (sequencing and/or determination of large rearrangements of a mismatch repair gene at least) were selected from the prospective database REM-CCR of Hospital Italiano de Buenos Aires (Clinical trials. Gov NCT02781337). Fifty families fulfilled Amsterdam criteria were analyzed. Pathogenic variants were found in 23 out of 50 (46%) families, being 21 pathogenic and 2 likely pathogenic. The 28.6% of the pathogenic variants were originally described in this series. Among them, the variant c.1911del in MSH2 in a family with breast cancer aggregation and a founder MLH1 mutation from Piedmont, Italy (c.2252_2253del) were identified. Affected genes include MSH2 (13 variants), MLH1 (9 variants), PMS2 (1 variant). Mutations detection rates was 46%. Those families with an identified mutation (n=23) had a lower median age of cancer onset (46 vs. 50 years, p=0.02) and a higher incidence of extra-colorectal tumors (90.5% vs. 45.8%, p<0.01) than those without identified mutations (n=27). The implementation of genetic studies allowed characterizing demographic variables based on the identification of germline mutations associated with Lynch syndrome. Two groups, Síndrome de Lynch: impacto de la caracterización de familias en base a estudios genéticos 3 differentiated by the age of cancer onset and the incidence of extracolonic tumors were characterized (AU)

Metabolic oligosaccharide engineering of Plasmodium falciparum intraerythrocytic stages allows direct glycolipid analysis by mass spectrometry.

A recent addition to the arsenal of tools for glycome analysis is the use of metabolic labels that allow covalent tagging of glycans with imaging probes. In this work we show that N-azidoglucosamine was successfully incorporated into glycolipidic structures of Plasmodium falciparum intraerythrocytic stages. The ability to tag glycoconjugates selectively with a fluorescent reporter group permits TLC detection of the glycolipids providing a new method to quantify dynamic changes in the glycosylation pattern and facilitating direct mass spectrometry analyses. Presence of glycosylphosphatidylinositol and glycosphingolipid structures was determined in the different extracts. Furthermore, the fluorescent tag was used as internal matrix for the MALDI experiment making even easier the analysis.

Mutación fundadora en síndrome de Lynch tipo II / Founder mutation in Lynch syndrome

El síndrome de Lynch es la más frecuente de las neoplasias colorrectales hereditarias. Se origina por mutaciones germinales deletéreas familia-específicas en los genes que codifican proteínas de reparación del ADN: MLH1 (homólogo humano de mutL), MSH2 y MSH6 (homólogo humano de mutS 2 y 6, respectivamente), PMS2 (homólogo humano de PMS1 2) y MUTYH (homólogo humano de la ADN-glycosilasa mutY). La mutación c.2252_2253delAA, p.Lys751Serfs*3 en el exón 19 del gen MLH1 segrega con un haplotipo descripto en la región norte de Italia y cuyo origen fue atribuido a un efecto fundador. Esta mutación co-segrega con características típicas del síndrome de Lynch, incluyendo afectación temprana y múltiples tumores primarios en el mismo individuo, una alta frecuencia de cáncer pancreático, elevada inestabilidad microsatelital y falta de expresión de PMS2. En el presente trabajo se comunica dicha mutación en una paciente argentina con adenocarcinoma endometroide de útero en cuya historia familiar existen antecedentes de cáncer de colon diagnosticado antes de los 50 años en familiares de primer grado, reuniendo los criterios de Ámsterdam I y síndrome de Lynch II. Los polimorfismos presentes en la paciente coinciden con el haplotipo descripto en una región del norte de Italia. El alto grado de patogenicidad asociada a esta mutación hace imprescindible el estudio de todos los integrantes de las familias con cáncer hereditario permitiendo el diagnóstico genético pre-sintomático, la instauración de tratamientos o conductas preventivas y su seguimiento.

Lynch syndrome is the most frequent syndrome in hereditary colorectal cancer, a family-specific deleterious mutations in genes encoding DNA reparation proteins: MLH1 (mutL homolog 1), MSH2, MSH6 (mutS homolog 2 y 6, respectively), PMS2 (PMS1 homolog 2, mismatch repair system component) y MUTYH (mutY DNA glycosylase).The c.2252_2253delAA, p.Lys751Serfs*3 mutation in MLH1 gene segregates with a haplotype reported in the northern region of Italy and whose origin was attributed to a founder effect. This mutation co-segregates with typical characteristics of Lynch syndrome, including early age at onset and multiple primary tumors in the same individual, a high frequency of pancreatic cancer, high microsatellite instability and lack of PMS2 expression. This report describes a mutation in an Argentinian patient with endometrioid adenocarcinoma of uterus. Her first-degree relatives had a history of colon cancer diagnosed before 50 years, fulfilling the Amsterdam Criteria I and Lynch syndrome II. The high pathogenicity associated to this mutation makes necessary the study of all members from families with hereditary cancer, allowing pre-symptomatic genetic diagnosis, early assessment and the instauration of preventive treatments.