Molecular pathology of acute kidney injury in a choline-deficient model and fish oil protective effect.

PURPOSE: The aim of this work was to investigate the potential protective effects of fish oil on the basis of kidney transcriptomic data on a nutritional experimental model. METHODS: Male weanling Wistar rats were divided into four groups and fed choline-deficient (CD) and choline-supplemented (CS) diets with vegetable oil (VO) and menhaden oil (MO): CSVO, CDVO, CSMO and CDMO. Animals were killed after receiving the diets for 6 days. Total RNA was purified from the right kidney and hybridized to Affymetrix GeneChip Rat Gene 1.0 ST Array. Differentially expressed genes were analyzed. RESULTS: All CSVO, CSMO and CDMO rats showed no renal alterations, while all CDVO rats showed renal cortical necrosis. A thorough analysis of the differential expression between groups CSMO and CDMO was carried out. There were no differential genes for p < 0.01. The analysis of the differential expression between groups CSVO and CSMO revealed 32 genes, 11 were over-expressed and 21 were under-expressed in CSMO rats. CONCLUSIONS: This work was part of a large set of experiments and was used in a hypothesis-generating manner. The comprehensive analysis of genetic expression allowed confirming that menhaden oil has a protective effect on this nutritional experimental model and identifying 32 genes that could be responsible for that protection, including Gstp1. These results reveal that gene changes could play a role in renal injury.

[Clinical-pathological features and gene profile in colorectal cancer]. / Caracteres clínico-patológicos y perfil genético en el carcinoma colorrectal.

Colorectal cancer is the third most frequent cancer in men and the second most frequent in women, with a worldwide incidence of approximately 1.2 million new cases per year. Our primary objective was to study the relationship between clinical and histological features of individuals with colorectal cancer and the mutational status of codons 12 and 13 of the KRAS gene (7 validated mutations), in order to find a histopathological marker to mutated tumors. The secondary objective was to determine how many patients had additional mutations in codons 15 and 61 of the KRAS gene, and codon 600 of the BRAF gene, which could modify the tumor phenotype. Sixty individuals with colorectal cancer (30 wild-type subjects and 30 with validated mutations in codons 12 and 13 of the KRAS gene) were selected. Exons 2 and 3 of the KRAS gene, and exon 15 of the BRAF gene were amplified and sequenced. The data collected were reviewed by a descriptive, univariate and/or multivariate analysis, as appropriate. In conclusion, no relation was found between clinical and histological features of individuals with colorectal cancer and their mutational status for codons 12 and 13 of the KRAS gene. This suggests that those easily available data do not allow predicting the response to anti-EGFR therapy. In patients with advanced colorectal adenocarcinomas and KRAS wild-type status, further study of codon 600 of the BRAF gene could be required.

Intravascular Large B-Cell Lymphoma and Renal Clear Cell Carcinoma as Collision Tumor: A Case Report and Review of the Literature.

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma characterized by the selective growth of lymphoma cells within the lumina of vessels. The patient usually presents with nonspecific symptoms and a remarkable deterioration in performance status. The occurrence of synchronous IVLBCL and renal cell carcinoma (RCC) is extremely rare. A right kidney tumor was found in a 72-year-old man with a history of low back pain. The kidney was enlarged, with a tumor mass measuring 4.5 × 4 × 4 cm. Sections exhibited a RCC (clear cell type, nuclear grade I). Also an extensive tumor affecting capillaries and small veins was present, positive for CD45, CD20, BCL-2, and MUM1/IRF-4, consistent with IVLBCL. The lymphoma was circumscribed to the RCC. The final diagnosis was IVLBCL with a RCC as collision tumor. After that, with neurological findings, central nervous system compromise by lymphoma was made. The patient started a first cycle of chemotherapy, progressive deterioration of the sensorium, and positive blood cultures for Klebsiella pneumoniae and Escherichia coli. The patient died 8 days later of acute respiratory failure. No autopsy was done. IVLBCL is an aggressive and systemic disease characterized by massive proliferation of tumor cells without a known primary site. Clinical identification and histopathologic diagnosis are relevant issues in the therapeutic management of these lymphomas. Until now, only one case of IVLBCL coexisting with RCC has been reported. In this article, we report a second case of IVLBCL with RCC simultaneous, as an unusual collision tumor.

Variable number tandem repeats in the promoter region of prostacyclin synthase gene in choline deficient rats.

Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.

Genetic diversity and phylogeographic analysis of human herpesvirus type 8 (HHV-8) in two distant regions of Argentina: Association with the genetic ancestry of the population.

BACKGROUND: The genetic diversity of persistent infectious agents, such as HHV-8, correlates closely with the migration of modern humans out of East Africa which makes them useful to trace human migrations. However, there is scarce data about the evolutionary history of HHV-8 particularly in multiethnic Latin American populations. OBJECTIVES: The aims of this study were to characterize the genetic diversity and the phylogeography of HHV-8 in two distant geographic regions of Argentina, and to establish potential associations with pathogenic conditions and the genetic ancestry of the population. STUDY DESIGN: A total of 101 HIV-1 infected subjects, 93 Kaposi's Sarcoma (KS) patients and 411 blood donors were recruited in the metropolitan (MET) and north-western regions of Argentina (NWA). HHV-8 DNA was detected by ORF-26 PCR in whole blood, saliva and FFPE tissues. Then, ORF-26 and ORF-K1 were analyzed for subtype assignment. Mitochondrial DNA and Y chromosome haplogroups, as well as autosomal ancestry markers were evaluated in samples in which subtypes could be assigned. Phylogeographic analysis was performed in the ORF-K1 sequences from this study combined with 388 GenBank sequences. RESULTS: HHV-8 was detected in 50.7%, 59.2% and 8% of samples from HIV-1 infected subjects, KS patients and blood donors, respectively. ORF-K1 phylogenetic analyses showed that subtypes A (A1-A5), B1, C (C1-C3) and F were present in 46.9%, 6.25%, 43.75% and 3.1% of cases, respectively. Analyses of ORF-26 fragment revealed that 81.95% of strains were subtypes A/C followed by J, B2, R, and K. The prevalence of subtype J was more commonly observed among KS patients when compared to the other groups. Among KS patients, subtype A/C was more commonly detected in MET whereas subtype J was the most frequent in NWA. Subtypes A/C was significantly associated with Native American maternal haplogroups (p = 0.004), whereas subtype J was related to non-Native American haplogroups (p < 0.0001). Sub-Saharan Africa, Europe and Latin America were the most probable locations from where HHV-8 was introduced to Argentina. CONCLUSIONS: These results give evidence of the geographic circulation of HHV-8 in Argentina, suggest the association of ORF-26 subtype J with KS development and provide new insights about its relationship with ancient and modern human migrations and identify the possible origins of this virus in Argentina.

[Mutational status of BRAF and histopathological characteristics in cutaneous malignant melanoma]. / Estado mutacional de BRAF y parámetros histopatológicos en melanoma maligno cutáneo.

Malignant melanoma (MM) is the more aggressive form of skin cancer with a mortality rate in Argentina 1997-2001 = 1.1/100 000 in men and 0.6 in women. BRAF proto-oncogene is focus of intense research; its mutation is one of the main tumor promoters and occurs in approximately 50% of MM. Several drugs with clinical activity on BRAF mutations have been approved. The aim of the study is to evaluate the mutational status of BRAF (exon 15) in cutaneous MM biopsies and its relationship with histopathological characteristics. We carried out an observational, retrospective study of samples fixed in formaldehyde and paraffin embedded; reviewing age, sex, diagnosis, histopathological data, tumor size and percentage, viability for molecular analysis and melanin presence. We evaluated BRAF mutations with PCR/Sanger sequencing. For statistics we used Student's t test, Chi square, Wilcoxon and Fisher's exact test. We were able to purify and sequence 76% (38/49) samples, 13/38 (34%) from women and 25/38 (66%) from men, the median age being 70 years. Most frequent location: thorax 14/35 (40%). Histological type: Superficial spreading 18/38 (47%). Clark's levels, 11/38 (29%): I-II and 27/38 (71%): III, IV and V. Breslow's median: 1.6 mm. Radial growth phase 11/38 (29%) and 27/38 (71%) vertical. Presented mutations 16/38 (42%). As reported by other authors, no association was found between the mutational state of exon 15 and clinical or histopathological parameters.

El melanoma maligno es la forma más agresiva de cáncer de piel, con una tasa de mortalidad en Argentina 1997-2001 = 1.1/100 000 en varones y 0.6 en mujeres. El proto-oncogén BRAF es foco de intensa investigación, su mutación es uno de los principales promotores tumorales y pueden presentarse en 50% de los melanomas. Se han aprobado varios fármacos con actividad clínica sobre las mutaciones BRAF. El objetivo del trabajo es evaluar el estado mutacional de BRAF (exón 15) en biopsias con melanoma maligno cutáneo y su relación con las características histopatológicas. Realizamos un estudio observacional, retrospectivo, de muestras fijadas en formol e incluidas en parafina. Revisamos edad, sexo, diagnóstico y datos histopatológicos, tamaño y porcentaje tumoral, viabilidad para análisis molecular y presencia de melanina. Evaluamos mutaciones de BRAF con PCR/secuenciación Sanger. Utilizamos test de Student, Chi cuadrado, Wilcoxon y prueba exacta de Fisher. De 49 casos se pudo purificar y secuenciar el 76% (38/49), 13/38 (34%) mujeres y 25/38 (66%) varones, edad mediana 70 años. Localización más frecuente: tórax con 14/35 (40%). Tipo histológico: extensivo superficial 18/38 (47%). Niveles de Clark, 11/38 (29%): I-II y 27/38 (71%): III, IV y V. Mediana del Breslow: 1.6 mm. Fase de crecimiento radial 11/38 (29%) y 27/38 (71%) vertical. Presentaron mutaciones 16/38 (42%). Como lo informado por otros autores, no se encontró asociación entre el estado mutacional del exón 15 y los parámetros clínicos o histopatológicos.

[Flow cytometry for the study of mediastinal tumors with abundant lymphoid elements]. / La citometría de flujo en el estudio de tumores mediastinales ricos en elementos linfoides.

The anterior mediastinum is a common site of tumors with abundant lymphoid elements. Flow cytometry is a useful complementary technique to analyze this type of tumors, which provides qualitative and quantitative information. A differential diagnosis can be sometimes made between thymoma and precursor T-lymphoblastic lymphoma (T-LBL). Correct identification is of utmost importance for patient treatment. A total of 38 mediastinal tumors were analyzed, and samples were separated for flow cytometry. Flow cytometry data from thymomas and normal thymic tissue were compared with 42 cases of T-LBL from other anatomical locations. Among 38 mediastinal tumors, we found 6 benign lesions, 9 diffuse large B-cell lymphomas (DLBCL), 10 Hodgkin lymphomas (HL), 11 thymomas and 2 T-LL. Flow cytometry provided positive information in 24 cases, and defined lymphoid neoplastic cells immunophenotype or the typical lymphocytes accompanying thymomas. Flow cytometry helped differentiate 10 cases of HL and 4 benign lesions from other lymphomas (DLBCL, T-LBL, etc.). CD3, CD4 and CD8 expressions were most useful for the differential diagnosis of thymomas and T-LL. To conclude, flow cytometry is a valid complementary technique, which promptly provides information on mediastinal lesions, requiring small quantities of tissue for both early diagnosis and follow up of these diseases.

Performance Assessment of Epidermal Growth Factor Receptor Gene Sequencing According to Sample Size in Daily Practice Conditions.

Lung carcinoma is the main cause of cancer death worldwide. Adenocarcinoma molecular biomarkers have been discovered, and targeted therapies have been developed with encouraging results. The epidermal growth factor receptor gene is one of these biomarkers. Exons 18 to 21 should be studied in patients with advanced adenocarcinoma, who are candidates for treatment with tyrosine kinase inhibitors. The objective was to compare the performance of the determination in large and small samples in daily practice conditions, trying to adjust to published consensus guidelines. A retrospective observational study of 141 cases was carried out, with exons 19 and 21 sequencing. Sample size (small vs. large), including number of satisfactory polymerase chain reaction (PCR), sequencing, deletions, and mutations, were evaluated. In small biopsies, sample type, fragment number, and percentage of tumor per sample were analyzed. The results shown 114/141 (80.8) cases that met selection criteria; 60/114 (53%) were large (surgical) and 54/114 (47%) were small samples (19/54 endoscopic, 17/54 fine needle aspiration clots, 4/54 lymph nodes, 14/54 core and other). All large samples were satisfactory PCR, 56/60 (93%) satisfactory sequencing, and 12/56 (21%) had deletions in exon 19. Small samples were satisfactory PCRs in 50/54 (93%) cases, and satisfactory sequencing in 35/50 (65%), 8/35 (23%) showed alterations in exon 19, and 1/35 (3%) in exon 21. In conclusion, the proportion of samples unfit for the study of the epidermal growth factor receptor gene mutational status increased from 7% in large samples to 35% in small ones. Nineteen small samples were inconclusive, with cell blocks predominating, 10/19 (53%).

Follicular carcinoma presenting as autonomous functioning thyroid nodule and containing an activating mutation of the TSH receptor (T620I) and a mutation of the Ki-RAS (G12C) genes.

Most autonomous functioning thyroid nodules (AFTN) are benign thyroid follicular neoplasms. There are rare reports of malignant hot nodules, in which activating mutations of the TSH receptor (TSHR) were found. We report a case of follicular carcinoma presenting as an AFTN causing subclinical hyperthyroidism in a 64-year-old woman who had a 6-cm hot nodule in the left thyroid lobe. Genomic DNA was extracted from paraffin-embedded tissues from the tumor and extratumoral thyroid tissue. Sequence analyses revealed point mutations in two different genes: the normal ACC sequence at codon 620 of the TSHR gene was replaced by ATC, changing the threonine by isoleucine (T620I); and the wild-type GGT at codon 12 of Ki-RAS mutated to TGT, replacing glycine by cysteine (G12C). In transfection experiments the T620I mutant showed constitutive activity in terms of cyclic adenosine monophosphate (cAMP) production when permanently transfected in 3T3 cells. Here, we describe for the first time an activating mutation in 3codon 620 of the TSHR. In addition, the cancerous AFTN also contained a G12C Ki-RAS mutation. We hypothesize that the combination of these two mutations might have played an important role in both the hyperfunction of the tumor and the carcinogenetic process.

[Study of the sentinel lymph node. Diagnosis and treatment of cutaneous malignant melanoma stages I and II]. / Estudio del ganglio centinela diagnostico y tratamiento del melanoma maligno cutaneo, estadios I y II.

Survival at 5 years of patients with localized primary malignant melanoma is about 80%, compared with a 35% survival in case of lymph nodes involvement. Sentinel lymph node(s) from 45 subjects with diagnosis of malignant melanoma stage I or II was/were studied with hematoxylin-eosin (HE), immunohistochemistry (IHC) and molecular biology (MB) techniques. The population was divided into three groups: HE-/IHC+/MB+, where 67% patients died; HE-/IHC-/MB+, where 57% died; and HE-/IHC-/MB-, where 100% of the patients are alive, with no lymphadenectomy and a median follow-up of 60 months. Those subjects who showed negativity with all the three methods had a null recurrence rate. Data herein obtained suggest a new molecular oncological staging, which would allow the selection of patients with submicroscopic metastases for a complete treatment. Moreover, several patients with no lymph node metastases should not undergo lymphadenectomies, and overtreatment could therefore be avoided.

[Mantle cell lymphoma vs. atypical chronic lymphocytic leukemia. Use of immunohistochemistry, flow cytometry and molecular biology for their adequate typing]. / Linfoma del manto vs. leucemia linfatica crónica atipica. Utilización de inmunohistoquímica, citometría de flujo y biología molecular para su correcta tipificación.

The differential diagnosis of certain B CD5+ lymphoproliferative processes, such as mantle cell lymphoma (MCL) and atypical chronic lymphocytic leukemia (ACLL), is difficult. The aim of this study was to correlate morphological findings, cyclin D1 (cD1) detection by immunohistochemistry (IHC) and immunophenotype by flow cytometry (FC) with the results obtained by molecular biology in this type of neoplasias. We analyzed 20 samples classified as B CD5+ lymphoproliferative processes by FC. PCR was used for t(11;14) bcl-1/IgH determination. Histopathological and IHC studies for cD1 were done in 14 cases. Twelve cases were diagnosed as MCL, with positive cD1 in 5 (5/9), five as ACLL and three as B lymphoproliferative process. PCR revealed t(11;14) in 6/12 MCL and negative results in the other groups (0/8). Molecular biology evidenced translocation in 4/5 MCL positive for cD1 with IHC. The presence of translocation could be demonstrated by IHC and PCR in 7/12 MCL: 4 with both techniques, 2 with PCR alone, and 1 with IHC alone. These findings show a significant association between cD1 by IHC and bcl-1/ IgH gene detection by PCR, which implies that both techniques are complementary for MCL typing.

[Immunoglobulin heavy chain gene rearrangements in the monoclonal gammopathies]. / Rearreglos de genes de cadenas pesadas de las inmunoglobulinas en las gammapatias monoclonales.

Plasma cell neoplasia occurs as a result of the expansion of an immunoglobulin-secreting B-cells clones, known as monoclonal component or M component. Malignant neoplasias include multiple myeloma and Waldenstrom macroglobulinemia, while premalignant conditions comprise monoclonal gammopathies of unknown significance (MGUS). MGUS present a monoclonal component with no signs of multiple myeloma, Waldenström macroglobulinemia, primary amyloidosis or other disorders. Pathological, radiological and clinical features are required for the diagnosis. Approximately 25% of patients with MGUS will become multiple myeloma, primary amiloidosis, macroglobulinemia, or other lymphoproliferative disease, which would be a premyelomatous condition. The objective of this study was to determine the clinical implications of immunophenotyping by flow cytometry and of the detection of clonality by molecular biology. A total of 32 patients were studied. Seven of them were diagnosed with multiple myeloma, and 25 with monoclonal gammopathy under study. These 32 patients were divided into four groups, based on their clinical data and flow cytometry outcome. In patients with non-diagnostic flow cytometry detection of immunoglobulin heavy chain gene rearrangements by PCR was performed, and monoclonality was found in 59% of the cases. The study of immunoglobulin heavy chain gene rearrangements by molecular biology allows a more sensitive detection of clonality.

Sentinel lymph node: detection of micrometastases of melanoma in a molecular study.

INTRODUCTION: Lymph node status in patients with cutaneous malignant melanoma is the most important prognostic factor. Patients with clinically positive nodes (stage III) should undergo therapeutic lymphadenectomy; however, the surgical approach to the regional disease in patients with negative clinical examination (stage I and II) is still controversial. Selective lymphadenectomy consists of the intraoperative identification of the first node in the nodal basin, the sentinel lymph node (SLN). Routine examination, serial sectioning, and immunohistochemistry may underestimate the presence of tumor cells. PCR is a molecular biology technique that may be useful for the detection of malignant melanoma nodal metastases in the SLN. AIM: The aim of this study was to use tyrosinase messenger RNA (mRNA) amplification for the detection of micrometastases in fresh frozen SLNs. METHODS: 46 hematoxylin-eosin (HE)-negative sentinel node samples from 42 patients with malignant melanoma were included in this study. Formalin-fixed paraffin-embedded sections were immunostained with S-100 protein and HMB-45. A central portion of the node was submitted for PCR. This method was accomplished with a combination of reverse transcription and amplification of the tyrosinase complementary DNA and double- round PCR (nested reverse transcriptase [RT]-PCR). RESULTS: In 1 of the 42 SLN-negative patients, immunohistochemistry stains allowed the detection of micrometastases. With molecular biology, 14 of the 42 SLN patients were positive (33%); in another 12 (29%), only the nested RT-PCR was positive. Of the 42 patients, 24 were put into 3 groups and followed for a 5-year period with 1, 7, and 16 patients, respectively, in the groups. The first group involved 1 patient who had provided 2 SLN samples that were found to be SLN-positive using both techniques, immunohistochemistry stains and nested RT-PCR (he had hepatic metastasis and died 24 months after diagnosis). The second group, with only nested RT-PCR positive SLN samples, included 7 of 12 patients who were followed and had a median survival of 37 months; 4 died of widespread metastatic disease, the other 3 patients had event-free survival, but 1 consented to undergo a therapeutic lymphadenectomy as a result of a positive test. The last group consisting of 16 of 32 patients, with complete 5-year survival, who were SLN-negative with both techniques, immunohistochemistry stains and nested RT-PCR. Fourteen of the 16 (88%) were event-free survival during the follow-up, and 2 had local relapse. CONCLUSION: Tyrosinase mRNA amplification may be a negative prognostic factor for the detection of micrometastases in fresh frozen SLNs using molecular biology techniques.

Lymphoid and myeloid neoplasms involving cerebrospinal fluid: comparison of morphologic examination and immunophenotyping by flow cytometry.

We studied 53 samples of cerebrospinal fluid (CSF) by cytologic examination and immunophenotyping by flow cytometry. The samples were taken from 43 patients; 25 had a previous diagnosis of malignant lymphoma/leukemia and the remaining 18 a variety of other diseases involving the central nervous system (CNS). Lymphoma/leukemia was detected in 21 samples: 12 by morphologic examination and immunophenotyping and nine by immunophenotyping alone. There were two cases with a suspicious morphologic examination and negative immunophenotyping in which the final diagnosis were cryptococcal and viral meningitis. In the group of 18 patients, one was diagnosed as a primary malignant lymphoma of the CNS and was positive with cytology and immunophenotyping. The other 17 were negative with both methods and follow-up showed no evidence of lymphoma/leukemia. This study shows that morphologic examination combined with flow cytometry enhances the detection rate by 75% over morphologic examination alone in CSF samples.

[Detection of micrometastases of colorectal carcinoma in lymph nodes]. / Detección de micrometástasis de carcinoma de colon en ganglios linfáticos.

Dissemination of lymph nodes is a known prognostic factor in colorectal carcinoma. Micrometastases in lymph nodes can be missed when studied by routine techniques. We analyzed 162 lymph nodes from 30 patients with colonic carcinoma and using routine techniques, they were classified as follows: two Dukes A; nineteen Dukes B; and nine Dukes C. A patient with benign colon disease served as negative control. Lymph nodes were all sectioned in halves, with one of the halves stored in liquid nitrogen for molecular biology examination by carcinoembryonic antigen expression. The other formalin-fixed and paraffin embedded halves were saved for both pathologic and immunohistochemical examination. For Dukes A and Dukes B tumors, reverse transcriptase-polymerase chain reaction (RT-PCR) had a 50% higher sensitivity in the detection of micrometastases. The expression of carcinoembryonic antigen (CEA) was detected in all Dukes C cases, which were considered as positive controls. These results showed that RT-PCR has a higher sensitivity in the detection of micrometastases than routine techniques, including immunohistochemistry.

Estado mutacional de BRAF y parámetros histopatológicos en melanoma maligno cutáneo / Mutational status of BRAF and histopathological characteristics in cutaneous malignant melanoma

El melanoma maligno es la forma más agresiva de cáncer de piel, con una tasa de mortalidad en Argentina 1997-2001 = 1.1/100 000 en varones y 0.6 en mujeres. El proto-oncogén BRAF es foco de intensa investigación, su mutación es uno de los principales promotores tumorales y pueden presentarse en 50% de los melanomas. Se han aprobado varios fármacos con actividad clínica sobre las mutaciones BRAF. El objetivo del trabajo es evaluar el estado mutacional de BRAF (exón 15) en biopsias con melanoma maligno cutáneo y su relación con las características histopatológicas. Realizamos un estudio observacional, retrospectivo, de muestras fijadas en formol e incluidas en parafina. Revisamos edad, sexo, diagnóstico y datos histopatológicos, tamaño y porcentaje tumoral, viabilidad para análisis molecular y presencia de melanina. Evaluamos mutaciones de BRAF con PCR/secuenciación Sanger. Utilizamos test de Student, Chi cuadrado, Wilcoxon y prueba exacta de Fisher. De 49 casos se pudo purificar y secuenciar el 76% (38/49), 13/38 (34%) mujeres y 25/38 (66%) varones, edad mediana 70 años. Localización más frecuente: tórax con 14/35 (40%). Tipo histológico: extensivo superficial 18/38 (47%). Niveles de Clark, 11/38 (29%): I-II y 27/38 (71%): III, IV y V. Mediana del Breslow: 1.6 mm. Fase de crecimiento radial 11/38 (29%) y 27/38 (71%) vertical. Presentaron mutaciones 16/38 (42%). Como lo informado por otros autores, no se encontró asociación entre el estado mutacional del exón 15 y los parámetros clínicos o histopatológicos.

Malignant melanoma (MM) is the more aggressive form of skin cancer with a mortality rate in Argentina 1997-2001 = 1.1/100 000 in men and 0.6 in women. BRAF proto-oncogene is focus of intense research; its mutation is one of the main tumor promoters and occurs in approximately 50% of MM. Several drugs with clinical activity on BRAF mutations have been approved. The aim of the study is to evaluate the mutational status of BRAF (exon 15) in cutaneous MM biopsies and its relationship with histopathological characteristics. We carried out an observational, retrospective study of samples fixed in formaldehyde and paraffin embedded; reviewing age, sex, diagnosis, histopathological data, tumor size and percentage, viability for molecular analysis and melanin presence. We evaluated BRAF mutations with PCR/Sanger sequencing. For statistics we used Student's t test, Chi square, Wilcoxon and Fisher's exact test. We were able to purify and sequence 76% (38/49) samples, 13/38 (34%) from women and 25/38 (66%) from men, the median age being 70 years. Most frequent location: thorax 14/35 (40%). Histological type: Superficial spreading 18/38 (47%). Clark´s levels, 11/38 (29%): I-II and 27/38 (71%): III, IV and V. Breslow´s median: 1.6 mm. Radial growth phase 11/38 (29%) and 27/38 (71%) vertical. Presented mutations 16/38 (42%). As reported by other authors, no association was found between the mutational state of exon 15 and clinical or histopathological parameters.

Helicobacter pylori and oral pathology: relationship with the gastric infection.

Helicobacter pylori (H. pylori) has been found in the oral cavity and stomach, and its infection is one of the most frequent worldwide. We reviewed the literature and conducted a Topic Highlight, which identified studies reporting an association between H. pylori-infection in the oral cavity and H. pylori-positive stomach bacterium. This work was designed to determine whether H. pylori is the etiologic agent in periodontal disease, recurrent aphthous stomatitis (RAS), squamous cell carcinoma, burning and halitosis. Record selection focused on the highest quality studies and meta-analyses. We selected 48 articles reporting on the association between saliva and plaque and H. pylori-infection. In order to assess periodontal disease data, we included 12 clinical trials and 1 meta-analysis. We evaluated 13 published articles that addressed the potential association with RAS, and 6 with squamous cell carcinoma. Fourteen publications focused on our questions on burning and halitosis. There is a close relation between H. pylori infection in the oral cavity and the stomach. The mouth is the first extra-gastric reservoir. Regarding the role of H. pylori in the etiology of squamous cell carcinoma, no evidence is still available.

Estudio patológico intraoperatorio en la cirugía tiroidea: ¿cuánto contribuye a la estrategia quirúrgica? / Intraoperative pathologic evaluation in thyroid surgery: how much does it contribute to surgical strategy?

Antecedentes: el papel del estudio patológico intraoperatorio (EPI) en cirugía tiroidea ha sido discutido largamente y es todavía motivo de controversia. Objetivo: estimar los resultados del EPI en el diagnóstico de malignidad, su relación con la biopsia por punción-aspiración preoperatoria con aguja fina (PAAF) y el estudio patológico diferido (EPD), así como su contribución al cambio en la estrategia quirúrgica en cirugía tiroidea. Material y métodos: revisión retrospectiva de las historias clínicas de 773 pacientes operados por patología tiroidea entre enero de 2014 y diciembre de 2015. En todos se efectuó EPI y EPD; a 686 (89%) pacientes también se les efectuó la biopsia por PAAF preoperatoria. Resultados: los resultados del EPI fueron benigno en 215 pacientes (27,8%), maligno en 419 (54,2%) y no definitivo en 139 (18,0%). Cuando estos resultados fueron comparados con la EPD se encontraron 19 casos (8,8%) de falsos negativos y 4 (0,95%) de falsos positivos. Considerando solo los resultados definitivos, el EPI tuvo sensibilidad 95%, especificidad 98%, valor predictivo positivo 99%, valor predictivo negativo 91% y exactitud 91%. Cuando se comparó el EPI con la PAAF preoperatoria, los valores de sensibilidad más bajos (44%) correspondieron a las categorías de Bethesda III y IV. El EPI influyó en la estrategia quirúrgica en 95 pacientes (12,28%): en 53 (6,8%), la hemitiroidectomía cambió a tiroidectomía total; en 37 (4,8%), el diagnóstico de metástasis ganglionares permitió realizar un vaciamiento modificado de cuello, y en 5 (0,6%) ocurrieron ambas situaciones. Conclusión: el EPI tuvo altos valores de utilidad diagnóstica cuando se compararon con el EPD. También se correlacionó con la PAAF preoperatoria, pero tuvo menos utilidad en las categorías Bethesda III y IV. El EPI contribuyó a cambiar la decisión de técnica quirúrgica en un grupo de pacientes y evitar una segunda operación.

Background: the role of intraoperative pathologic evaluation (IPE) in thyroid surgery has largely been discussed and it is still controversial. Objective: to estimate the results of IPE in diagnosis of malignancy, its correlation with preoperative fine needle aspiration (FNA) biopsy and permanent pathologic evaluation (PPE), and its contribution to change surgical strategy in thyroid surgery. Materials and methods: retrospective chart review of 773 patients operated on for thyroid disease between January 2014 and December 2015. All patients underwent IPE and PPE; 686 (89%) patients had also preoperative FNA biopsy. Results: IPE resulted benign in 215 patients (27.8%), malignant in 419 (54.2%) and non definitive in 139 (18.0%). When these results were compared with PPE, 19 cases were false negative (8.8%) and 4 false positive (0.95). Considering only definitive results, IPE had sensitivity 95%, specificity 98%, positive predictive value 99%, negative predictive value 91% and accuracy 91%. When IPE was compared with preoperative FNA biopsy, lowest values of sensitivity (44%) corresponded with Bethesda categories III and IV. IPE influenced surgical strategy in 95 patients (12.28%): in 53 (6.8%) hemithyroidectomy changed to total thyroidectomy, in 37 (4.8%) lymph node metastases diagnosis allowed to perform modified neck dissection, and in 5 (0.6%) both situations occurred. Conclusion: IPE had high values of diagnostic utility when compared with PPE. It also correlated with preoperative FNA biopsy, but had less utility in Bethesda categories III and IV. IPE contributed to change surgical technical decision in a subset of patients and avoid a second operation.