Carcinoma colorrectal serrado: caracterización morfológica, inmunohistoquímica y molecular / Morphological, immunohistochemical and molecular features of serrated colorectal carcinoma

El carcinoma serrado (CS) es un tipo de carcinoma colorrectal (CCR) recientemente reconocido por la OMS que representa entre el 7,5 y el 9,2% de los CCR. Los criterios histológicos para su diagnóstico fueron propuestos por investigadores finlandeses y han sido validados recientemente por autores españoles. Distintos estudios demuestran que el CS tiene peor pronóstico que el CCR convencional. Además, se han estudiado factores histológicos con valor pronóstico, la expresión inmunohistoquímica de proteínas relacionadas con la gemación tumoral y reparación del ADN y la incidencia de inestabilidad de microsatélites (MSI) y de mutaciones en KRAS y BRAF. En consonancia con las observaciones clínicas, demostramos que los CS presentan características histológicas de mal pronóstico, un patrón característico de expresión de proteínas en el frente invasivo, y estatus MSI y perfil de mutaciones diferente a los CCR no serrados. Estos hallazgos sugieren que el diagnóstico correcto del CS puede tener importantes implicaciones clínicas(AU)

Serrated carcinoma (SC) is a subtype of colorectal carcinoma (CRC). Recently, the WHO estimated that it accounts for 7.5-9.2% of all CRCs. The diagnostic criteria proposed by Finnish authors, have been confirmed by Spanish research. Various studies show that SC has a worse prognosis than conventional CRC carcinoma ( CC ). Histological features with prognostic significance have been identified in SC, including the immunohistochemical expression of proteins implicated in tumour-budding formation and DNA repair, the microsatellite instability (MSI) status and the occurrence of KRAS and BRAF mutation. In agreement with clinical evidence, we have shown histologically that SC, with a distinct pattern of proteins at the invasive front and oncogene mutations, has a worse prognosis than CC. Thus, an accurate diagnosis of SC is of clinical importance(AU)

Brote de fungemia por Candida parapsilosis en una unidad de cuidados intensivos neonetal: genotipificación molecular basada en el estudio de microsatélites / Outbreak of fungemia caused by Candida parapsilosis in a neonatal intensive care unit: Molecular investigation through microsatellite analysis

Antecedentes. Las infecciones oportunistas son un problema cada vez más frecuente en los hospitales, y Candida parapsilosis se está convirtiendo en un importante patógeno nosocomial, sobre todo en las unidades de cuidados intensivos neonatales (UCIN) donde ha sido responsable de brotes de candidiasis invasoras. En recién nacidos, los factores de riesgo de infección por C. parapsilosis incluyen la prematuridad, bajo peso al nacer, la hospitalización prolongada, los catéteres venosos centrales permanentes, alimentación parenteral, las emulsiones grasas por vía intravenosa y la administración de antibióticos de amplio espectro. Para esclarecer el origen y evolución de estos brotes hospitalarios, pueden utilizarse métodos moleculares, que permiten estudiar las variaciones genéticas entre los aislamientos clínicos. Objetivos. El objetivo del presente estudio fue estudiar un brote de C. parapsilosis en la UCIN del Hospital das Clinicas, Facultad de Medicina de Botucatu, un hospital de asistencia terciaria de São Paulo, Brasil, usando una técnica de genotipificación molecular basada en el estudio de microsatélites. Métodos. Durante un período de 43 días en la UCIN, se diagnosticaron un total de 11 casos de fungemia por C. parapsilosis. Para confirmar el brote, todas las cepas se sometieron a análisis de tipificación molecular utilizando la técnica de microsatélites. Resultados. Se observó el mismo genotipo en 9 de las 11 cepas estudiadas, lo que permitió confirmar la presencia de un brote de C. parapsilosis en la UCIN del hospital. Conclusiones. El presente estudio revela que el análisis de marcadores de microsatélites puede ser de utilidad para los objetivos ya mencionados. Es de destacar la importancia de usar técnicas moleculares para la detección precoz de brotes hospitalarios y la introducción eficaz de medidas preventivas, en especial en las UCIN(AU)

Background. Opportunistic infections are an increasingly common problem in hospitals, and the yeast Candida parapsilosis has emerged as an important nosocomial pathogen, especially in neonatal intensive care units (NICUs) where it has been responsible for outbreak cases. Risk factors for C. parapsilosis infection in neonates include prematurity, very low birth weight, prolonged hospitalization, indwelling central venous catheters, hyperalimentation, intravenous fatty emulsions and broad spectrum antibiotic therapy. Molecular methods are widely used to elucidate these hospital outbreaks, establishing genetic variations among strains of yeast. Aims. The aim of this study was to detect an outbreak of C. parapsilosis in an NICU at the “Hospital das Clinicas”, Faculty of Medicine of Botucatu, a tertiary hospital located in São Paulo, Brazil, using the molecular genotyping by the microsatellite markers analysis. Methods. A total of 11 cases of fungemia caused by C. parapsilosis were identified during a period of 43 days in the NICU. To confirm the outbreak all strains were molecularly typed using the technique of microsatellites. Results. Out of the 11 yeast samples studied, nine showed the same genotypic profile using the technique of microsatellites. Conclusions. Our study shows that the technique of microsatellites can be useful for these purposes. In conclusion, we detected the presence of an outbreak of C. parapsilosis in the NICU of the hospital analyzed, emphasizing the importance of using molecular tools, for the early detection of hospital outbreaks, and for the introduction of effective preventive measures, especially in NICUs(AU)

Molecular basis of colorectal cancer: towards an individualized management?

Colorectal cancer (CRC) has become a highly relevant condition nowadays. In this respect, advances in the understanding of its molecular basis are key for an adequate management. From the time when the adenoma-carcinoma sequence was formulated as a carcinogenesis model to this day, when, among other things, three major carcinogenic pathways have been identified, the CRC concept has evolved from that of a single disease to the notion that each CRC is a differentiated condition in itself. The suppressor or chromosome instability pathway, the mutator or microsatellite instability pathway, and the methylator or CpG island methylation pathway allow various phenotypes to be identified within CRC. Similarly, the presence of different changes in certain genes confers several behaviors on CRC from both the prognostic and responsive standpoints to specific therapies. However, this apparent complexity does help develop the clinical management of this disease through the identification of novel, more specific therapy targets, and also markers for various behaviors within the condition, which will most likely lead us to an individualized management for these patients(AU)

Microsatellite instability in radiation-induced murine tumours; influence of tumour type and radiation quality.

PURPOSE: To investigate microsatellite instability (MSI) in radiation-induced murine tumours, its dependence on tissue (haemopoietic, intestinal, mammary, brain and skin) and radiation type. MATERIALS AND METHODS: DNA from spontaneous, X-ray or neutron-induced mouse tumours were used in Polymerase Chain Reactions (PCR) with mono- or di-nucleotide repeat markers. Deviations from expected allele size caused by insertion/deletion events were assessed by capillary electrophoresis. RESULTS: Tumours showing MSI increased from 16% in spontaneously arising tumours to 23% (P = 0.014) in X-ray-induced tumours and rising again to 83% (P << 0.001) in neutron-induced tumours. X-ray-induced Acute Myeloid Leukaemias (AML) had a higher level of mono-nucleotide instability (45%) than di-nucleotide instability (37%). Fifty percent of neutron-induced tumours were classified as MSI-high for mono-nucleotide markers and 10% for di-nucleotide markers. Distribution of MSI varied in the different tumour types and did not appear random. CONCLUSIONS: Exposure to ionising radiation, especially neutrons, promotes the development of MSI in mouse tumours. MSI may therefore play a role in mouse radiation tumourigenesis, particularly following high Linear Energy Transfer (LET) exposures. MSI events, for a comparable panel of genome-wide markers in different tissue types, were not randomly distributed throughout the genome.

Functional DNA repair system analysis in haematopoietic progenitor cells using host cell reactivation.

Deficiencies in individual DNA repair systems are involved in both de novo and therapy-related acute myeloid leukaemia (t-AML), as indicated by genetic markers involving nucleotide excision repair (NER gene polymorphisms), double-strand-break (DSB) or mismatch repair (microsatellite instability (MSI)). We modified a host cell reactivation (HCR) assay for functional DNA repair system analysis of living primary haematopoietic cells; 2 x 10(5) normal peripheral blood lymphocytes (PBLs) and cord blood CD34+ progenitor cells were cryopreserved, thawed and transfected with 75-250 ng luciferase reporter plasmid (pCMVLuc) using DEAE-dextran (0.1 mg/mL) in a transfection volume of 250 microL. We obtained luciferase activities of approximately 300-fold above background in CD34+ progenitor cells and approximately 2000-fold in PBLs, thus rendering these cells applicable for DNA repair analysis. We then evaluated the NER (UV-irradiated pCMVLuc) and DSB repair capacity (linearized pCMVLuc) of normal lymphocytes and several leukaemic cell lineages. Kasumi-1 and HL-60 AML cells exhibited a reduced NER capacity compared to normal GM03715 lymphocytes, PBLs and CD34+ progenitor cells (6.2 +/- 0.9%, 6.5 +/- 0.9% vs. 12.3 +/- 1.8%, 13.5 +/- 0.7% and 13.5 +/- 2.0%, respectively). Kasumi-1 AML tells exhibited a reduced DSB repair capacity compared to AG10107 and GM03715 normal lymphocytes as well as CEM acute T-cell lymphoblastic leukaemia cells (6.4 +/- 0.8% vs. 10.8 +/- 0.7%, 27.3 +/- 1.1% and 20.5 +/- 1.6%, respectively). The modified HCR assay can be used for functional DNA repair analysis in living cells of patients with pre- and post-leukaemic conditions as well as in leukaemic blasts to elucidate the role of DNA repair in de novo and t-AML leukaemogenesis and to determine the individual susceptibility to t-AML prior to chemotherapy.

Genetic effects of X-ray and carbon ion irradiation in head and neck carcinoma cell lines.

The effects of X-ray and carbon ion irradiation on DNA and genes in head and neck carcinoma cells were examined. Four head and neck cancer cell lines (squamous cell carcinoma, salivary gland cancer, malignant melanoma, normal keratinocyte) were treated with 1, 4, and 7 GyE of carbon ion, or 1, 4, and 8 Gy of X-ray, respectively. DNA and RNA in the treated cells were extracted and purified. PCR-LOH (polymerase chain reaction-loss of heterozygosity) analysis with 6 microsatellite regions on chromosome 17 was performed to determine DNA structural damage, and then microarray analysis was performed to reveal changes in gene expression. PCR-LOH analysis detected high LOH in cells treated by radiation, indicating that most of the damage by X-ray occurred in the target region on one of the homologous chromosomes. However, carbon ion caused homo-deletion, which means deletion of the counterparts in both homologous chromosomes.

Genética del cáncer colorrectal y poliposis / Genetics of colorectal cancer and polyposis

En la última década se ha producido un avance muy significativo en el campo del cáncer colorrectal hereditario. Estos avances se han producido principalmente en la identificación del síndrome de Lynch o cáncer colorrectal hereditario no polipósico, mediante criterios clínicos y técnicas moleculares (inmunohistoquímica, inestabilidad de microsatélites), así como en la reciente implicación del gen MYH en la carcinogénesis colorectal. Las mutaciones bialélicas en el gen MYH causan, por un lado, una forma de poliposis adenomatosa familiar atenuada con herencia recesiva, y por otro lado, predisponen al desarrollo de cáncer colorrectal. Es fundamental conocer los síndromes hereditarios asociados al cáncer colorrectal para así poder detectar los individuos potencialmente portadores de mutaciones, y ser derivados a centros de referencia especializados para la realización de estudios moleculares y la aplicación de programas de cribado y vigilancia específicos (AU)

In the last decade, highly significant advances have been made in the field of hereditary colorectal cancer. These advances have been produced mainly in the identification of Lynch syndrome or hereditary non-polyposic colorectal cancer through clinical criteria and molecular techniques (immunohistochemistry, microsatellite instability), as well as in the recent implication of the MYH gene in colorectal carcinogenesis. Biallelic mutations in the MYH gene cause a form of attenuated familial adenomatous polyposis, with recessive inheritance, on the one hand, and predispose affected individuals to the development of colorectal cancer, on the other hand. It is essential to determine the hereditary syndromes associated with colorectal cancer in order to detect individuals potentially carrying mutations and to refer these individuals to specialized centers performing molecular studies and specific screening and monitoring programs (AU)