Implementation of upfront DPYD genotyping with a low-cost and high-throughput assay to guide fluoropyrimidine treatment in cancer patients.

OBJECTIVES: Genetic variants in the dihydropyrimidine dehydrogenase (DPYD ) gene are associated with reduced dihydropyrimidine dehydrogenase enzyme activity and can cause severe fluoropyrimidine-related toxicity. We assessed the frequency of the four most common and well-established DPYD variants associated with fluoropyrimidine toxicity and implemented a relatively low-cost and high-throughput genotyping assay for their detection. METHODS: This study includes 457 patients that were genotyped for the DPYD c.1129-5923C>G, c.1679T>G, c.1905 + 1G>A and c.2846A>T variants, either by Sanger sequencing or kompetitive allele specific PCR (KASP) technology. Of these, 172 patients presented toxicity during treatment with fluoropyrimidines (post-treatment group), and 285 were tested before treatment (pretreatment group). RESULTS: Heterozygous DPYD variants were identified in 7.4% of the entire series of 457 patients, being the c.2846A>T the most frequent variant. In the post-treatment group, 15.7% of the patients presented DPYD variants, whereas only 2.5% of the patients in the pretreatment group presented a variant. The KASP assays designed in this study presented 100% genotype concordance with the results obtained by Sanger sequencing. CONCLUSIONS: The combined assessment of the four DPYD variants in our population increases the identification of patients at high risk for developing fluoropyrimidine toxicity, supporting the upfront routine implementation of DPYD variant genotyping. Furthermore, the KASP genotyping assay described in this study presents a rapid turnaround time and relatively low cost, making upfront DPYD screening feasible in clinical practice.

Formación universitaria a distancia para la inserción laboral de personas con discapacidad intelectualUna experiencia en la UNED / University Distance Learning for the Labor Market Integration of People with Intellectual Disabilities: An Experience at UNED

El presente artículo describe una experiencia de formación universitaria a distancia, la cual se ha basado en los principios del diseño universal para el aprendizaje y la accesibilidad cognitiva para promover la inserción laboral de personas con discapacidad intelectual. El principal objetivo de esta experiencia formativa fue contribuir al desarrollo de competencias que ayudaran a estudiantes con discapacidad intelectual a avanzar en su actualización profesional para la inserción laboral en la Administración Pública española. Participaron 179 personas con discapacidad intelectual. Los resultados mostraron una tasa de éxito del 89 % y una tasa de abandono del 11 %. A través de un cuestionario ad hoc, se evaluó el grado de satisfacción de los diferentes elementos del diseño curricular de esta experiencia de aprendizaje a distancia. En particular, los participantes mostraron índices de satisfacción elevada con los contenidos seleccionados, los materiales y recursos multimedia disponibles en el aula virtual, así como con los posibles beneficios de la instrucción de estrategias de autorregulación emocional. Cabe concluir que el diseño curricular implementado ha sido muy satisfactorio y ha mejorado las habilidades para el empleo que propicien la inserción laboral de los estudiantes. (AU)

This paper focuses on the description of an experience carried out in a Spanish distance university, which was based on the principles of universal design for learning and cognitive accessibility to promote the labour insertion of people with intellectual disabilities. The main objective of the training proposal was to contribute to the development of some competencies that would help students with intellectual disabilities to improve their professional updating for job placement in the Spanish Public Administration. A total of 179 people with intellectual disabilities participated in the course. The results evidenced a high success rate of 89% and a low dropout rate of 11%. Through an ad hoc questionnaire, we evaluated the degree of learners´ satisfaction with different elements of the curricular design for this online learning experience. Particularly, participants reported high satisfaction rates with the selected contents, educational materials and multimedia resources available in the virtual classroom, as well as with the possible benefits of the instruction of emotional self-regulation strategies. It can be concluded that the instructional design has led to high satisfaction and improved the employability abilities of the students to deal with the labour market. (AU)

Executive Functions and Improvement of Thinking: An Intervention Program to Enhance Deductive Reasoning Abilities.

Empirical and theoretical advances and application to society are moved at different speed. Application work is frequently developed later because it requires the integration of knowledge from different research areas. In the present paper, we integrate literature coming from diverse areas of research in order to design a deductive reasoning intervention, based on the involved executive functions. Executive functions include working memory (WM)'s online executive processes and other off-line functions such as task revising and planning. Deductive reasoning is a sequential thinking process driven by reasoners' meta-deductive knowledge and goals that requires the construction and manipulation of representations. We present a new theoretical view about the relationship between executive function and higher-level thinking, a critical analysis of the possibilities and limitations of cognitive training, and a metacognitive training procedure on executive functions to improve deductive reasoning. This procedure integrates direct instruction on deduction and meta-deductive concepts (consistency, necessity) and strategies (search for counterexamples and exhaustivity), together with the simultaneous training of WM and executive functions involved: Focus and switch attention, update WM representations, inhibit and revise intuitive responses, and control the emotional stress yielded by tasks. Likewise, it includes direct training of some complex WM tasks that demands people to carry out similar cognitive assignment than deduction. Our training program would be included in the school curriculum and attempts not only to improve deductive reasoning in experimental tasks, but also to increase students' ability to uncover fallacies in discourse, to automatize some basic logical skills, and to be able to use logical intuitions.

Exploring Saduria entomon (Crustacea Isopoda) as a New Source for Chitin and Chitosan Isolation.

Chitin and chitosan demand is growing very fast due to interest from industries such as pharmaceutical, cosmetic, agricultural and others. New sources for chitin and chitosan isolation are being extensively searched to fulfil this demand. In this paper, Saduria entomon a Baltic benthic crustacean, is evaluated as a source for chitin and chitosan isolation. Chitin and chitosan yield from S. entomon were 14.8 and 8.2%, respectively, in a similar range to other sources. Samples were characterized in terms of physicochemical properties (acetylation degree, molecular weight, thermal stability, and crystallinity) and two biological properties, antimicrobial activity and antioxidant activity were evaluated. Chitosan S. entomon exhibited antimicrobial activity against S. aureus but not against E. coli. An antioxidant activity of 20.98 TROLOX µmol equivalent/g polymer was detected for the chitosan sample. These properties are very promising for the use of this organism as a source for chitin and chitosan isolation in the biomedical field.

The role of working memory updating, inhibition, fluid intelligence, and reading comprehension in explaining differences between consistent and inconsistent arithmetic word-problem-solving performance.

Children's performance in arithmetic word problems (AWPs) predicts their academic success and their future employment and earnings in adulthood. Understanding the nature and difficulties of interpreting and solving AWPs is important for theoretical, educational, and social reasons. We investigated the relation between primary school children's performance in different types of AWPs and their basic cognitive abilities (reading comprehension, fluid intelligence, inhibition, and updating processes). The study involved 182 fourth- and fifth-graders. Participants were administered an AWP-solving task and other tasks assessing fluid intelligence, reading comprehension, inhibition, and updating. The AWP-solving task included comparison problems incorporating either the adverb more than or the adverb less than, which demand consistent or inconsistent operations of addition or subtraction. The results showed that consistent problems were easier than inconsistent problems. Efficiency in solving inconsistent problems is related to inhibition and updating. Moreover, our results seem to indicate that the consistency effect is related to updating processes' efficiency. Path analyses showed that reading comprehension was the most important predictor of AWP-solving accuracy. Moreover, both executive functions-updating and inhibition-had a distinct and significant effect on AWP accuracy. Fluid intelligence had both direct and indirect effects, mediated by reading comprehension, on the overall measure of AWP performance. These domain-general factors are important factors in explaining children's performance in solving consistent and inconsistent AWPs.

KRAS and NRAS mutational analysis in plasma ctDNA from patients with metastatic colorectal cancer by real-time PCR and digital PCR.

PURPOSE: Mutations in the KRAS and NRAS (RAS) genes are negative predictors of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC). The detection of mutations in circulating tumor DNA (ctDNA) has emerged as a less invasive strategy to assess the molecular profile of mCRC patients. We aimed to perform RAS mutational analysis in ctDNA from mCRC patients using BEAMing Digital PCR (OncoBEAM) and Idylla ctDNA qPCR and evaluate the concordance rate with RAS mutational status in tumor tissue and between these two methodologies with different limits of detection. METHODS: Blood samples were collected from 47 mCRC patients previously tested for RAS mutations in tumor tissue. DNA was extracted from plasma using the QIAamp Circulating Nucleic Acid Kit, and RAS mutation analysis was conducted using OncoBEAM RAS CRC and Idylla ctRAS assays. RESULTS: The overall agreement between tumor tissue and ctDNA analyses was 83% and 78.7% using the OncoBEAM and Idylla assays, respectively, with the concordance being 96.2% and 88.5% in naive treatment patients. The overall agreement between OncoBEAM and Idylla ctDNA analyses was 91.7%. CONCLUSIONS: Analysis of ctDNA is a viable strategy for clinical management of mCRC patients. Although the OncoBEAM assay sensitivity is somewhat higher, the fully automated Idylla platform also has good performance, while being cheaper and much less labor-intensive, for the detection of RAS mutations in plasma, either at diagnosis or after progression when considering anti-EGFR treatment rechallenge.

Executive Functions and Improvement of Thinking: An Intervention Program to Enhance Deductive Reasoning Abilities

Empirical and theoretical advances and application to society are moved at different speed. Application work is frequently developed later because it requires the integration of knowledge from different research areas. In the present paper, we integrate literature coming from diverse areas of research in order to design a deductive reasoning intervention, based on the involved executive functions. Executive functions include working memory (WM)’s online executive processes and other off-line functions such as task revising and planning. Deductive reasoning is a sequential thinking process driven by reasoners’ meta-deductive knowledge and goals that requires the construction and manipulation of representations. We present a new theoretical view about the relationship between executive function and higher-level thinking, a critical analysis of the possibilities and limitations of cognitive training, and a metacognitive training procedure on executive functions to improve deductive reasoning. This procedure integrates direct instruction on deduction and meta-deductive concepts (consistency, necessity) and strategies (search for counterexamples and exhaustivity), together with the simultaneous training of WM and executive functions involved: Focus and switch attention, update WM representations, inhibit and revise intuitive responses, and control the emotional stress yielded by tasks. Likewise, it includes direct training of some complex WM tasks that demands people to carry out similar cognitive assignment than deduction. Our training program would be included in the school curriculum and attempts not only to improve deductive reasoning in experimental tasks, but also to increase students’ ability to uncover fallacies in discourse, to automatize some basic logical skills, and to be able to use logical intuitions. (AU)

The Comprehension of Counterfactual Conditionals: Evidence From Eye-Tracking in the Visual World Paradigm.

Three experiments tracked participants' eye-movements to examine the time course of comprehension of the dual meaning of counterfactuals, such as "if there had been oranges then there would have been pears." Participants listened to conditionals while looking at images in the visual world paradigm, including an image of oranges and pears that corresponds to the counterfactual's conjecture, and one of no oranges and no pears that corresponds to its presumed facts, to establish at what point in time they consider each one. The results revealed striking individual differences: some participants looked at the negative image and the affirmative one, and some only at the affirmative image. The first experiment showed that participants who looked at the negative image increased their fixation on it within half a second. The second experiment showed they do so even without explicit instructions, and the third showed they do so even for printed words.

The nonsense mutation MSH2 c.2152C>T shows a founder effect in Portuguese Lynch syndrome families.

The mutational spectrum of the MMR genes is highly heterogeneous, but specific mutations are observed at high frequencies in well-defined populations or ethnic groups, due to founder effects. The MSH2 mutation c.2152C>T, p.(Gln718*), has occasionally been described in Lynch families worldwide, including in Portuguese Lynch syndrome families. During genetic testing for Lynch syndrome at the Portuguese Oncology Institutes of Porto and Lisbon, this mutation was identified in 28 seemingly unrelated families. In order to evaluate if this alteration is a founder mutation, haplotype analysis using microsatellite and SNP markers flanking the MSH2 gene was performed in the 28 probands and 87 family members. Additionally, the geographic origin of these families was evaluated and the age of the mutation estimated. Twelve different haplotypes were phased for 13 out of the 28 families and shared a conserved region of ∼3.6 Mb. Based on the mutation and recombination events observed in the microsatellite haplotypes and assuming a generation time of 25 years, the age estimate for the MSH2 mutation was 273 ± 64 years. The geographic origins of these families were mostly from the Northern region of Portugal. Concluding, these results suggest that the MSH2 c.2152C>T alteration is a founder mutation in Portugal with a relatively recent origin. Furthermore, its high proportion indicates that screening for this mutation as a first step, together with the previously reported Portuguese founder mutations, may be cost-effective in genetic testing of Lynch syndrome suspects of Portuguese ancestry.

A New Look to a Classic Issue: Reasoning and Academic Achievement at Secondary School.

Higher-order thinking abilities such as abstract reasoning and meaningful school learning occur sequentially. The fulfillment of these tasks demands that people activate and use all of their working memory resources in a controlled and supervised way. The aims of this work were: (a) to study the interplay between two new reasoning measures, one mathematical (Cognitive Reflection Test) and the other verbal (Deductive Reasoning Test), and a third classical visuo-spatial reasoning measure (Raven Progressive Matrices Test); and (b) to investigate the relationship between these measures and academic achievement. Fifty-one 4th grade secondary school students participated in the experiment and completed the three reasoning tests. Academic achievement measures were the final numerical scores in seven basic subjects. The results demonstrated that cognitive reflection, visual, and verbal reasoning are intimately related and predicts academic achievement. This work confirms that abstract reasoning constitutes the most important higher-order cognitive ability that underlies academic achievement. It also reveals the importance of dual processes, verbal deduction and metacognition in ordinary teaching and learning at school.

Elucidating potential utilization of Portuguese common bean varieties in rice based processed foods.

The present study was aimed at studying the physico-chemical and functional properties of 31 Portuguese common bean varieties. In addition, the whole bean flours (WBF) and starch isolates (SI) of three representative bean varieties and their rice: bean blends (70:30; 50:50) were assessed for amylose content, thermal and pasting properties in view of supplementation in rice based processed foods. Bean varieties showed significant differences in protein content (20.78-27.10%), fat content (1.16-2.18%), hydration capacity (95.90-149.30%), unhydrated seeds (4.00-40.00%), γ tocopherol (3.20-98.05 mg/100 g fat), δ tocopherol (0.06-4.72 mg/100 g fat) and pasting behavior. Amylose content of WBF (11.4-20.2%) was significantly lower than rice flour (23.51%) whereas SI of beans (40.00-47.26%) had significantly higher amylose content than SI of rice (28.13%). DSC results showed that WBF (11.4-20.2 °C) had significantly broader and lower gelatinization temperature range (∆Tr) than corresponding SI (20.9-23.1 °C). WBF had significantly lower pasting viscosity due to low starch content and compositional matrix effect as compared to SI. Setback viscosities of WBF and rice: bean blends was lower than rice flour. Low setback viscosities of rice:bean blends may be used to prevent syneresis and stabilizing the quality of frozen foods in rice based processed foods.

POLE somatic mutations in advanced colorectal cancer.

Despite all the knowledge already gathered, the picture of somatic genetic changes in colorectal tumorigenesis is far from complete. Recently, germline and somatic mutations in the exonuclease domain of polymerase epsilon, catalytic subunit (POLE) gene have been reported in a small subset of microsatellite-stable and hypermutated colorectal carcinomas (CRCs), affecting the proofreading activity of the enzyme and leading to misincorporation of bases during DNA replication. To evaluate the role of POLE mutations in colorectal carcinogenesis, namely in advanced CRC, we searched for somatic mutations by Sanger sequencing in tumor DNA samples from 307 cases. Microsatellite instability and mutation analyses of a panel of oncogenes were performed in the tumors harboring POLE mutations. Three heterozygous mutations were found in two tumors, the c.857C>G, p.Pro286Arg, the c.901G>A, p.Asp301Asn, and the c.1376C>T, p.Ser459Phe. Of the POLE-mutated CRCs, one tumor was microsatellite-stable and the other had low microsatellite instability, whereas KRAS and PIK3CA mutations were found in one tumor each. We conclude that POLE somatic mutations exist but are rare in advanced CRC, with further larger studies being necessary to evaluate its biological and clinical implications.

Validation of a Next-Generation Sequencing Pipeline for the Molecular Diagnosis of Multiple Inherited Cancer Predisposing Syndromes.

Despite the growing knowledge of the genetic background behind the cancers that occur in a context of hereditary predisposition, personal or family cancer history may not be clear enough to support directional gene testing. Defined targeted next-generation sequencing gene panels allow identification of the causative disease mutations of multigene syndromes and differential diagnosis for syndromes with phenotypically overlapping characteristics. Herein, we established a next-generation sequencing analysis pipeline for the molecular diagnosis of multiple inherited cancer predisposing syndromes using the commercially available target sequencing panel TruSight Cancer. To establish the analysis pipeline, we included 22 control samples with deleterious mutations covering all genes currently analyzed at our institution by standard Sanger sequencing. We tested the pipeline using 51 samples from patients with a clinical diagnosis of neurofibromatosis type 1 (NF1), 10 of which without previous molecular characterization of the causative NF1 mutations. We propose a thoroughly validated analysis pipeline that combines Isaac Enrichment, Burrows-Wheeler Aligner Enrichment, and NextGENe for the alignment and variant calling, and GeneticistAssistant for variant annotation and prioritization. This pipeline allowed the identification of disease-causing mutations in all 73 patients, including a large duplication of 37 bp in NF1. We show that high sensitivity and specificity can be achieved by using multiple bioinformatic tools for alignment and variant calling and careful variant filtering, having in mind the clinical question.

Performance of Lynch syndrome predictive models in quantifying the likelihood of germline mutations in patients with abnormal MLH1 immunoexpression.

Lynch syndrome (LS) accounts for up to 4 % of all colorectal cancers (CRC). Detection of a pathogenic germline mutation in one of the mismatch repair genes is the definitive criterion for LS diagnosis, but it is time-consuming and expensive. Immunohistochemistry is the most sensitive prescreening test and its predictive value is very high for loss of expression of MSH2, MSH6, and (isolated) PMS2, but not for MLH1. We evaluated if LS predictive models have a role to improve the molecular testing algorithm in this specific setting by studying 38 individuals referred for molecular testing and who were subsequently shown to have loss of MLH1 immunoexpression in their tumors. For each proband we calculated a risk score, which represents the probability that the patient with CRC carries a pathogenic MLH1 germline mutation, using the PREMM1,2,6 and MMRpro predictive models. Of the 38 individuals, 18.4 % had a pathogenic MLH1 germline mutation. MMRpro performed better for the purpose of this study, presenting a AUC of 0.83 (95 % CI 0.67-0.9; P < 0.001) compared with a AUC of 0.68 (95 % CI 0.51-0.82, P = 0.09) for PREMM1,2,6. Considering a threshold of 5 %, MMRpro would eliminate unnecessary germline mutation analysis in a significant proportion of cases while keeping very high sensitivity. We conclude that MMRpro is useful to correctly predict who should be screened for a germline MLH1 gene mutation and propose an algorithm to improve the cost-effectiveness of LS diagnosis.

Efecto diferencial del estilo educativo paterno y materno en la agresividad durante la adolescencia / Differential effect of paternal and maternal parenting style during adolescence

El objetivo principal de este trabajo fue analizar el efecto diferencial de las dimensiones del estilo educativo paterno y materno en la agresividad del adolescente. Participaron 271 estudiantes de entre 10 y 14 años cumplimentando medidas de autoinforme. Los resultados muestran que los chicos puntúan más alto que las chicas en agresividad física y verbal, y que la agresividad física aumenta con la edad. Se encuentra una elevada coincidencia entre las diferentes dimensiones del estilo educativo paterno y materno, así como puntuaciones más elevadas de las madres que de los padres en todas las dimensiones. Los análisis de correlación muestran valores significativos negativos entre casi todas las dimensiones del estilo educativo paterno y materno y la agresividad. El análisis de regresión arroja diferencias en el efecto de las dimensiones estilo educativo parental paterno vs materno sobre la agresividad. Se discuten los resultados respecto al papel del control psicológico y de la promoción de la autonomía por parte de los progenitores en la variación del nivel de agresividad durante la transición de la niñez a la adolescencia

The main goal of the present study was to analyze the differential effect of paternal and maternal parenting styles on aggressiveness during adolescence. The sample was made up of 271 students, aged 10-14, who completed questionnaires. The analysis of the data shows that boys display higher scores in physical and verbal aggressiveness than girls, with physical aggressiveness increasing with age. A high level of coincidence between paternal and maternal parenting style´s dimensions was found as well as higher scores for mothers than fathers in all the dimensions. Correlation analysis shows significant negative values in almost all dimensions of paternal and maternal parenting styles. Regression analysis reveals differences in paternal vs. maternal parenting style regarding aggressiveness. The effect of psychological control and promotion of autonomy on the level of aggressiveness during the transition from childhood to adolescence is discussed

Implementation of next-generation sequencing for molecular diagnosis of hereditary breast and ovarian cancer highlights its genetic heterogeneity.

Molecular diagnosis of hereditary breast and ovarian cancer (HBOC) by standard methodologies has been limited to the BRCA1 and BRCA2 genes. With the recent development of new sequencing methodologies, the speed and efficiency of DNA testing have dramatically improved. The aim of this work was to validate the use of next-generation sequencing (NGS) for the detection of BRCA1/BRCA2 point mutations in a diagnostic setting and to study the role of other genes associated with HBOC in Portuguese families. A cohort of 94 high-risk families was included in the study, and they were initially screened for the two common founder mutations with variant-specific methods. Fourteen index patients were shown to carry the Portuguese founder mutation BRCA2 c.156_157insAlu, and the remaining 80 were analyzed in parallel by Sanger sequencing for the BRCA1/BRCA2 genes and by NGS for a panel of 17 genes that have been described as involved in predisposition to breast and/or ovarian cancer. A total of 506 variants in the BRCA1/BRCA2 genes were detected by both methodologies, with a 100 % concordance between them. This strategy allowed the detection of a total of 39 deleterious mutations in the 94 index patients, namely 10 in BRCA1 (25.6 %), 21 in BRCA2 (53.8 %), four in PALB2 (10.3 %), two in ATM (5.1 %), one in CHEK2 (2.6 %), and one in TP53 (2.6 %), with 20.5 % of the deleterious mutations being found in genes other than BRCA1/BRCA2. These results demonstrate the efficiency of NGS for the detection of BRCA1/BRCA2 point mutations and highlight the genetic heterogeneity of HBOC.

Executive Functions and the Improvement of Thinking Abilities: The Intervention in Reading Comprehension.

In this paper, we propose a preliminary theory of executive functions that address in a specific way their relationship with working memory (WM) and higher-level cognition. It includes: (a) four core on-line WM executive functions that are involved in every novel and complex cognitive task; (b) two higher order off-line executive functions, planning and revision, that are required to resolving the most complex intellectual abilities; and (c) emotional control that is involved in any complex, novel and difficult task. The main assumption is that efficiency on thinking abilities may be improved by specific instruction or training on the executive functions necessary to solving novel and complex tasks involved in these abilities. Evidence for the impact of our training proposal on WM's executive functions involved in higher-level cognitive abilities comes from three studies applying an adaptive program designed to improve reading comprehension in primary school students by boosting the core WM's executive functions involved in it: focusing on relevant information, switching (or shifting) between representations or tasks, connecting incoming information from text with long-term representations, updating of the semantic representation of the text in WM, and inhibition of irrelevant information. The results are consistent with the assumption that cognitive enhancements from the training intervention may have affected not only a specific but also a more domain-general mechanism involved in various executive functions. We discuss some methodological issues in the studies of effects of WM training on reading comprehension. The perspectives and limitations of our approach are finally discussed.

Co-occurrence of nonsense mutations in MSH6 and MSH2 in Lynch syndrome families evidencing that not all truncating mutations are equal.

The majority of pathogenic mismatch repair (MMR) gene mutations detected in Lynch syndrome patients are truncating (frameshift or nonsense). However, the classification of terminal truncating mutations is sometimes difficult and predictive testing based on non-deleterious variants can have very serious consequences. Here, we report eight probands that have two germline nonsense mutations, namely MSH6 c.1030C>T, p.(Gln344Ter) and MSH2 c.2785C>T, p.(Arg929Ter), and one additional patient who presented only the MSH2 mutation previously reported as deleterious. The novel MSH6 truncating mutation was classified as deleterious, as it is predicted to encode a protein with loss of 1017 amino acid residues. The MSH2 mutation, which is expected to encode a protein lacking six amino acid residues, was considered a variant of unknown significance. Five tumors of the eight double-mutant individuals had normal MSH2 expression, whereas MSH6 immunoexpression was lost in all evaluable cases. None of the variants were detected in normal controls or associated with other MMR germline mutations in our series. This study emphasizes that not all truncating mutations are equal and that one must be cautious in the interpretation of the presumed deleterious effect of terminal frameshift or nonsense mutations.

Target gene mutational pattern in Lynch syndrome colorectal carcinomas according to tumour location and germline mutation.

BACKGROUND: We previously reported that the target genes in sporadic mismatch repair (MMR)-deficient colorectal carcinomas (CRCs) in the distal colon differ from those occurring elsewhere in the colon. This study aimed to compare the target gene mutational pattern in microsatellite instability (MSI) CRC from Lynch syndrome patients stratified by tumour location and germline mutation, as well as with that of sporadic disease. METHODS: A series of CRC from Lynch syndrome patients was analysed for MSI in genes predicted to be selective MSI targets and known to be involved in several pathways of colorectal carcinogenesis. RESULTS: The most frequently mutated genes belong to the TGF-ß superfamily pathway, namely ACVR2A and TGFBR2. A significantly higher frequency of target gene mutations was observed in CRC from patients with germline mutations in MLH1 or MSH2 when compared with MSH6. Mutations in microsatellite sequences (A)7 of BMPR2 and (A)8 of MSH3 were significantly more frequent in the distal CRC. Additionally, we observed differences in MSH3 and TGFBR2 mutational frequency between Lynch syndrome and sporadic MSI CRC regarding tumour location. CONCLUSIONS: Our results indicate that the pattern of genetic changes differs in CRC depending on tumour location and between Lynch syndrome and sporadic MSI CRC, suggesting that carcinogenesis can occur by different pathways even if driven by generalised MSI.

Identification of previously unrecognized FAP in children with Gardner fibroma.

Fibromatous soft tissue lesions, namely desmoid-type fibromatosis and Gardner fibroma, may occur sporadically or as a result of inherited predisposition (as part of familial adenomatous polyposis, FAP). Whereas desmoid-type fibromatosis often present ß-catenin overexpression (by activating CTNNB1 somatic variants or APC biallelic inactivation), the pathogenetic mechanisms in Gardner fibroma are unknown. We characterized in detail Gardner fibromas diagnosed in two infants to evaluate their role as sentinel lesions of previously unrecognized FAP. In the first infant we found a 5q deletion including APC in the tumor and the novel APC variant c.4687dup in constitutional DNA. In the second infant we found the c.5826_5829del and c.1678A>T APC variants in constitutional and tumor DNA, respectively. None of the constitutional APC variants occurred de novo and both tumors showed nuclear staining for ß-catenin and no CTNNB1 variants. We present the first comprehensive characterization of the pathogenetic mechanisms of Gardner fibroma, which may be a sentinel lesion of previously unrecognized FAP families.