Next-generation Sequencing for ALK and ROS1 Rearrangement Detection in Patients With Non-small-cell Lung Cancer: Implications of FISH-positive Patterns.

BACKGROUND: Detection of ALK and ROS1 gene rearrangements in non-small-cell lung cancer is required for directing patient care. Although fluorescence in situ hybridization (FISH) and immunohistochemistry have been established as gold standard methods, next-generation sequencing (NGS) platforms are called to be at least equally successful. Comparison of these methods for translation into daily use is currently under investigation. PATIENTS AND METHODS: Forty non-small-cell lung cancer paraffin-embedded samples with previous ALK (n = 33) and ROS1 (n = 7) FISH results were examined with the Oncomine Focus Assay and tested for ALK and ROS1 immunoreactivity. Clinical implications of concurrent molecular alterations and concordance between methods were evaluated. RESULTS: NGS was successful in 32 (80%) cases: 25 ALK and 7 ROS1. Few concomitant alterations were detected: 1 ALK rearranged case had an ALK p.L1196M-resistant mutation, 4 had CDK4, MYC, and/or ALK amplifications, and 1 ROS1 rearranged case showed a FGFR4 amplification. Comparison between techniques revealed 5 (16%) discordant cases that had lower progression-free survival than concordant cases: 7.6 (95% confidence interval, 2.2-13) versus 19.4 (95% confidence interval, 10.1-28.6). Remarkably, 4 of these cases had isolated 3' signal FISH pattern (P = .026). CONCLUSION: Our data support that the identification of 3' isolated signal FISH pattern in ALK and ROS1 cases might suggest a false-positive result. NGS seems a reliable technique to assess ALK and ROS1 rearrangements, offering the advantage over immunohistochemistry of detecting other molecular alterations with potential therapeutic implications.

Correlation of mRNA-PCA3 urine levels with the new grading system in prostate cancer / Correlación de mRNA-PCA3 en orina con el nuevo sistema de gradación de cáncer de próstata

Purpose: To evaluate the PCA3 (Prostate Cancer 3 gene) as a tool to improve prostate cancer (PCa) screening and its capability to predict PCa aggressiveness. Patients and methods: A retrospective study with data from consecutive patients with suspected PCa seen in the urology department between November 2009 and April 2016 and who were candidates for prostate biopsy. A total of 1038 urine samples were tested in our laboratory with a kit that generated a PCA3 score (s-PCA3). A prostate biopsy was recommended only in those patients with s-PCA3≥35. Associations between variables were analyzed using the R software. Results: In patients with a positive s-PCA3 (44.5%), a subsequent biopsy was recommended. Of a total of 151 biopsies studied, 56.3% yielded a diagnosis of PCa. The probability of a positive biopsy increased as the s-PCA3 increased (p=0.041). The percentage of affected cylinders increased as the s-PCA3 increased (p=0.015). A statistically significant relationship was observed between s-PCA3 and both the Gleason score and the Grade Group (p=0.001 and 0.008, respectively). The best log-linear models and a logistic model confirmed the relationships shown previously with Fisher's exact tests. Conclusions: S-PCA3 may serve as an additional marker to reduce the indication for biopsies and avoid overdiagnosis and overtreatment of patients with suspected PCa. The prognostic significance of s-PCA3 was confirmed, as it was associated with tumor volume and Gleason score. Importantly, to our knowledge this is the first time that an association has been demonstrated between s-PCA3 and the new Grade Group

Objetivo: Evaluar el estudio de PCA3 (gen Prostate Cancer 3) en orina como test complementario para mejorar el cribado de cáncer de próstata (CaP), así como su capacidad de predecir la agresividad tumoral antes de la biopsia. Pacientes y métodos: En este estudio retrospectivo se incluyeron pacientes consecutivos con sospecha de CaP y candidatos a biopsia, que se presentaron en la consulta del urólogo entre noviembre de 2009 y abril de 2016. Se testaron en nuestro laboratorio un total de 1.038 muestras de orina con un kit que generó un PCA3 score (s-PCA3). Se recomendó la biopsia en aquellos pacientes con s-PCA3≥35. Las asociaciones entre variables se analizaron con el software R. Resultados: En los pacientes con s-PCA3 positivo (44,5%) se recomendó la realización de una biopsia. Se estudiaron un total de 151 biopsias de las que un 56,3% fueron diagnosticadas de CaP. La probabilidad de obtener una biopsia positiva aumentó a medida que lo hacia el s-PCA3 (p=0,041). El porcentaje de cilindros afectados aumentó a medida que lo hacía el s-PCA3 (p=0,015). El s-PCA3 presentó una relación estadísticamente significativa con el grado de Gleason (p=0,001) y el grado grupo (p=0,008). El mejor modelo Log-lineal, así como el modelo logístico confirmaron las relaciones observadas previamente con las pruebas exactas de Fisher. Conclusiones: El s-PCA3 es una herramienta complementaria que permite reducir la indicación de biopsias y evitar el sobrediagnóstico y sobretratamiento de pacientes con sospecha de CaP. La significación pronóstica del s-PCA3 fue confirmada al demostrarse su asociación con el volumen tumoral y el grado de Gleason. Según la información de la que disponemos, este es el primer estudio en el que se demuestra la asociación entre el s-PCA3 y el nuevo sistema de gradación del CaP

Correlation of mRNA-PCA3 urine levels with the new grading system in prostate cancer.

PURPOSE: To evaluate the PCA3 (Prostate Cancer 3 gene) as a tool to improve prostate cancer (PCa) screening and its capability to predict PCa aggressiveness. PATIENTS AND METHODS: A retrospective study with data from consecutive patients with suspected PCa seen in the urology department between November 2009 and April 2016 and who were candidates for prostate biopsy. A total of 1038 urine samples were tested in our laboratory with a kit that generated a PCA3 score (s-PCA3). A prostate biopsy was recommended only in those patients with s-PCA3≥35. Associations between variables were analyzed using the R software. RESULTS: In patients with a positive s-PCA3 (44.5%), a subsequent biopsy was recommended. Of a total of 151 biopsies studied, 56.3% yielded a diagnosis of PCa. The probability of a positive biopsy increased as the s-PCA3 increased (p=0.041). The percentage of affected cylinders increased as the s-PCA3 increased (p=0.015). A statistically significant relationship was observed between s-PCA3 and both the Gleason score and the Grade Group (p=0.001 and 0.008, respectively). The best log-linear models and a logistic model confirmed the relationships shown previously with Fisher's exact tests. CONCLUSIONS: S-PCA3 may serve as an additional marker to reduce the indication for biopsies and avoid overdiagnosis and overtreatment of patients with suspected PCa. The prognostic significance of s-PCA3 was confirmed, as it was associated with tumor volume and Gleason score. Importantly, to our knowledge this is the first time that an association has been demonstrated between s-PCA3 and the new Grade Group.

Carcinoma seroso peritoneal y adenocarcinoma mucinoso apendicular sincrónicos. Estudio inmunohistoquímico y molecular / Synchronous serous peritoneal carcinoma and mucinous appendicular adenocarcinoma. Immunohistochemical and molecular study

Paciente mujer de 60 años, en seguimiento por historia familiar de cáncer de mama y ovario, en la que se detectaron implantes tumorales peritoneales y depósitos de mucina en serosa apendicular. Los implantes peritoneales fueron diagnosticados de carcinoma seroso tipo ovárico/peritoneal con inmunofenotipo característico, siendo la mucina acelular. Se realizaron estudios de mutación de KRAS y BRAF mediante PCR que demostró la presencia de mutación GD12 únicamente en el componente mucinoso, lo que permitió mostrar la existencia de una doble neoplasia. La cirugía posterior confirmó la existencia sincrónica de un adenocarcinoma mucinoso apendicular y un carcinoma seroso peritoneal. Creemos que este caso permite ilustrar que la incorporación de los estudios moleculares en la actividad asistencial del patólogo puede aportarnos información adicional con valor diagnóstico (AU)

A 60 year old female with a family history of ovarian and breast cancer underwent a follow-up laparoscopic exploration which revealed peritoneal implants and mucinous deposits on the appendicular surface. The peritoneal implants were diagnosed as serous carcinoma with a characteristic immunophenotype, while the mucinous material was acellular. KRAS and BRAF mutation studies with PCR showed a GD12 mutation in the mucinous component only, suggesting the presence of a synchronous carcinoma. Subsequent cytorreductive surgery confirmed the presence of an infiltrating appendicular mucinous adenocarcinoma, synchronous with the peritoneal infiltrating serous carcinoma. We believe that this case, where the different immunohistochemical and molecular profiles allowed a correct diagnosis of two independent neoplasms, emphasizes the value of molecular studies in routine diagnostic procedure (AU)

EGFR mutations in lung cancer / Mutaciones de EGFR en cancer de pulmón

The study of epidermal growth factor receptor mutations has become essential for the treatment of lung cancer. The aim of this study was to find a correlation between morphological changes and EGFR mutational status using both immunohistochemistry and molecular techniques. We also analyzed the cross-reaction of the L858R mutation-specific monoclonal antibody in cases with HER2 amplification described previously in breast and gastric cancer. A series of 100 primary lung adenocarcinomas were examined. Exon 19 E746_A750del and exon 21 L858R mutations were studied using immunohistochemistry with two specific monoclonal antibodies. Gene mutational status was determined using real-time PCR or Sanger sequencing followed by real-time PCR when negative. EGFR mutations were detected in 22 cases (22%) by molecular techniques, being significantly more frequent in women, low grade carcinoma and lepidic subtype, (p-value <0.05 in all cases). In addition, in our series presence of tumoral necrosis correlated with absence of mutations. The anti-E746_A750del antibody achieved a 100% positive predictive value and a negative predictive value of 97.7% which could restrict the use of molecular techniques to the 7% of cases with an equivocal result. The antibody for L858R mutation showed inconsistent results compared to molecular techniques, giving false positive result in two adenocarcinomas with HER2 amplification. However, its negative predictive value was very high (98.9%). The use of real-time PCR identifies mutations not detected by the other two techniques. These new antibodies could be useful as a screening tool prior to EGFR molecular techniques (AU)

El estudio de las mutaciones de EGFR ha resultado ser esencial en el tratamiento del cáncer de pulmón. La finalidad de este trabajo ha sido estudiar la correlación entre los cambios morfológicos y el estado mutacional de EGFR utilizando técnicas de inmunohistoquímica y moleculares. Asimismo se analizó la reacción cruzada del anticuerpo anti-L858R en casos con amplificación de HER2 descrita previamente en cáncer de mama y gástrico. La serie consta de 100 adenocarcinomas pulmonares primarios. Las mutaciones E746_A750del exón-19 y L858R exón-21 se estudiaron por inmunohistoquímica con dos anticuerpos monoclonales específicos. El estado mutacional del gen se determinó mediante PCR en tiempo-real o secuenciación por Sanger seguida de PCR en tiempo-real cuando resultó negativa. Se detectaron mutaciones de EGFR en 22 casos (22%) por técnicas moleculares, siendo significativamente más frecuente en mujeres, carcinoma de bajo grado y subtipo lepídico, (p-valor<0,05 en todos los casos). Además, en nuestra serie la presencia de necrosis tumoral se correlaciona con ausencia de mutaciones. El anticuerpo anti-E746_A750del presentó un valor-predictivo-positivo del 100% y un valor-predictivo-negativo del 97,7%, lo que podría restringir el uso de técnicas moleculares al 7% de casos no-concluyentes. El anticuerpo anti-L858R mostró resultados inconsistentes en comparación con las técnicas moleculares, dando resultado falso-positivo en dos adenocarcinomas con amplificación de HER2. Sin embargo, su valor-predictivo-negativo es muy alto (98,9%). El uso de PCR en tiempo-real rescata mutaciones no detectadas por las otras dos técnicas. Estos nuevos anticuerpos podrían ser útiles como herramienta de cribado previo al estudio de EGFR mediante técnicas moleculares (AU)

Expresión inmunohistoquímica de CK19 en variantes comunes del carcinoma de mama y en subtipos histológicos infrecuentes / CK19 immunoexpression in common breast carcinomas and in special histological subtypes

El estudio del ganglio centinela es una parte esencial de la estadificación en cáncer de mama. El One-Step Nucleic Acid Amplification (OSNA) es un ensayo molecular intraoperatorio que mide la cantidad de ARNm de citoqueratina 19 (CK19) presente en la totalidad del ganglio. Debido a su mayor sensibilidad y especificidad en comparación con el examen histológico convencional se está incorporando progresivamente para la detección de metástasis en ganglio centinela, con la recomendación de demostrar la expresión inmunohistoquímica de CK19 en una biopsia previa para evitar falsos negativos. El objetivo de nuestro estudio fue evaluar la expresión de CK19 en carcinomas de mama con especial énfasis en los subtipos especiales o poco frecuentes. Se estudiaron un total de 337 carcinomas de mama distribuidos en tres series: una retrospectiva de casos no seleccionados estudiados sobre «tissue microarrays», otra retrospectiva de secciones completas, enriquecida con subtipos histológicos especiales y/o perfil molecular triple-negativo y una serie prospectiva de biopsias, sobre secciones completas, previas al estudio OSNA. Considerando los resultados de nuestras tres series, la gran mayoría de los carcinomas de mama presentan positividad difusa de CK19; por tanto, sería muy poco probable, especialmente en variantes comunes, obtener un falso negativo de OSNA debido a la falta de expresión de CK19 en el tumor primario. Se demuestra expresión heterogénea únicamente en casos de subtipos especiales (carcinoma apocrino, adenoide quístico y medular) y/o perfil TN (AU)

Sentinel lymph node assessment is an essential part of the staging procedure in breast cancer. Increasingly, One-Step Nucleic Acid Amplification (OSNA), an intraoperative molecular assay that measures the amount of cytokeratin 19 (CK19) mRNA present in the whole of the sentinel lymph node, is being used in the detection of sentinel lymph node metastasis, due to its superior sensitivity and equal specificity compared with conventional histological examination. CK19 positive immunostaining in a previous biopsy is recommended to avoid false negative results with OSNA analysis. The aim of our study was to assess the degree of CK19 positivity in series of breast carcinomas with particular emphasis on special histological subtypes. The total of 337 breast carcinomas studied were distributed in three series as follows: a retrospective unselected series studied on tissue microarray, a series of whole sections enriched for special histological subtypes and triple negative carcinomas, and a prospective series of biopsies studied in whole sections, prior to a routine OSNA assay. The results of our three series revealed that the great majority of breast carcinomas exhibits a diffuse CK19 positivity. Therefore it would be highly unlikely, especially in frequent variants, to have a false negative OSNA result due to lack of CK19 expression in the primary tumour. Heterogeneous expression was only observed in patients with infrequent variants (apocrine, adenoid cystic and medullary carcinomas) and/or TN profile (AU)

Cross-reactivity of EGFR L858R mutation-specific antibody in HER2 positive gastric adenocarcinomas / Reacción cruzada del anticuerpo específico para la mutación EGFR L858R en los adenocarcinomas gástricos HER2 positivos

Recently, the study of the EGFR mutations in lung cancer has become mandatory due to their usefulness in target therapy. Lately, the use of specific antibodies to study the most prevalent of these mutations has been introduced. The newly published discovery of the existence of a cross-reaction between the HER2 protein and the EGFR L858R-specific antibody in breast cancer led us to corroborate this cross-reactivity in other tumors; specifically, we have chosen gastric carcinomas where HER2 is routinely evaluated as a molecular therapy driver. Our series consists of 15 primary gastric carcinomas, 7 HER2 cases positive for overexpression/amplification and 8 negative cases for both techniques. EGFR L858R mutation was studied with immunohistochemistry and complemented with real time PCR when positive. Immunohistochemistry assay with EGFR L858R was positive in 5 of the HER2 positive carcinomas (71%), none of which was confirmed by PCR, and negative in all HER2 negative carcinomas. Conclusions: The EGFR L858R antibody gives false positive results in most gastric carcinomas with HER2 overexpression/amplification, confirming the results described previously in breast cancer. It is also important to bear in mind that HER2 has also been described in other carcinomas, including lung cancer (AU)

En los últimos años, el estudio de las mutaciones de EGFR en cáncer de pulmón se ha convertido en esencial por su utilidad como diana terapéutica. Recientemente se ha introducido el uso de anticuerpos para la detección de las mutaciones más prevalentes. El descubrimiento de la existencia de una reacción cruzada entre la proteína HER2 y el anticuerpo específico EGFFR L858R, recientemente publicado en cáncer de mama, nos condujo a explorar la existencia de dicha reacción cruzada en otros tumores. Seleccionamos en primer lugar el cáncer gástrico, en el que se evalúa HER2 de forma rutinaria para la identificación de candidatos a tratamiento con terapia dirigida. La serie incluyó 15 carcinomas gástricos primarios, 7 casos positivos para sobreexpresión/amplificación de HER2 y 8 casos negativos para ambas técnicas. La presencia de la mutación EGFR L858R se estudió por inmunohistoquímica, y en caso de resultado positivo se complementó con el estudio molecular por PCR a tiempo real para su confirmación. El estudio inmunohistoquímico de EGFR L858R resultó positivo en 5 de los carcinomas HER2 positivos (71%), sin que ninguno se confirmara por PCR, y fue negativo para todos los carcinomas HER2 negativos. Conclusiones: El anticuerpo EGFR L858R presenta resultado falso positivo en la mayoría de carcinomas con sobreexpresión/amplificación de HER2, confirmando los resultados descritos previamente en cáncer de mama. Es importante tener presente que la presencia de HER2 ha sido descrita en otros carcinomas, incluido el cáncer de pulmón (AU)

Prospective validation of the microsatellite instability prediction models: RERtest6 and RERtest8

El estudio de la inestabilidad de microsatélites (MSI) es altamente recomendable en todos los carcinomas colorrectales, tanto como una primera aproximación para identificar posibles pacientes con síndrome de Lynch, como debido a su valor pronóstico y a su asociación con una mala respuesta a los regímenes basados en 5-fluorouracilo. A pesar de estas evidencias, la aplicación del estudio de MSI en la práctica general es bastante limitada. Este hecho pone de relieve la necesidad de herramientas de cribado para facilitar la implementación del estudio de MSI. Este trabajo presenta la validación de dos modelos de predicción previamente publicados, RERtest6 y RERtest8, basados en parámetros clínico-patológicos y dirigidos a una población no seleccionada por edad. La serie incluye 206 tumores colorrectales primarios de 199 pacientes, a los que se les aplicaron los modelos de predicción que contienen 6 ó 8 parámetros, respectivamente, antes de la evaluación del estado de MSI con el panel NCI consenso o el kit de MSI Promega. Se detectó alta inestabilidad de microsatélites (MSI-H) en 21 casos (10,1%). Ambos modelos han confirmado su robustez y fueron capaces de mantener valores predictivos negativos cercanos al 95%, lo que permite la reducción del número de casos que requieren un estudio molecular al 10%. Asimismo, la naturaleza de los parámetros incluidos en los modelos, que en su mayoría ya forman parte de un examen histopatológico de rutina, los convierten en una herramienta útil y de fácil aplicación en la práctica clínica (AU)

Determining microsatellite instability status (MSI) is now highly recommended for all diagnosed colorectal carcinomas, both as a first approach to identify putative Lynch syndrome patients, and as a valuable prognostic indicator as it is associated with a poor response to 5-fluorouracil-based regimes. However, generally the implementation of MSI testing is still quite limited, suggesting the need for screening tools which would simplify MSI testing. This study presents the validation of two previously published prediction models, RERtest6 and RERtest8, based on clinicopathological features and without age restriction. The series includes 206 primary colorectal tumors from 199 patients, to which the models containing 6 or 8 parameters were applied before the assessment of MSI status, using the consensus NCI panel or the MSI Promega kit. High-level microsatellite instability (MSI-H) was detected in 21 cases (10.1%). Both models confirmed their reliability and were able to maintain negative predictive values close to 95%, reducing the number of cases to be tested by molecular methods to 10%. Furthermore, the nature of the parameters included in the models, mostly already part of a routine histopathological examination, makes them a useful tool that can be easily implemented into routine practice (AU)

Cross-reactivity of EGFR mutation-specific immunohistochemistry assay in HER2-positive tumors.

The coexpression of HER2 and EGFR L858R in a solitary nodule removed from the lung, whose mutation was not confirmed by molecular techniques, made us think about the possible existence of a cross-reaction between HER2 and the EGFR L858R-specific antibody. Our study was designed to further analyze the existence of this cross-reaction and stress the need to exclude a metastatic breast cancer when dealing with EGFR L858R-positive cases. The series consists of 42 primary breast carcinomas, 22 HER2 positive for overexpression and amplification, and 20 negative for both. EGFR mutations were studied by immunohistochemistry and confirmed using real-time PCR when positive. Immunohistochemistry assay with EGFR L858R was positive in 19 (86%) of the HER2-positive breast carcinomas and negative in all HER2-negative carcinomas. The EGFR L858R antibody gives false-positive results in most of the breast carcinomas with HER2 overexpression/amplification. As a consequence, it is essential to confirm any EGFR L858R-positive cases by molecular methods or at least discard the presence of HER2 overexpression/amplification before rendering a diagnosis. It is also important to consider that HER2 has been described in other carcinomas such as urothelial, gastric or ovarian, as well as lung, although infrequently.

ERG expression and prostatic adenocarcinoma.

ERG gene rearrangement has been identified as a highly specific alteration that is present in 40-50 % of prostate carcinomas. The standardization of an immunohistochemical assay with a novel anti-ERG antibody recently described would have significant diagnostic value. The aims of this study were to identify the incidence of this rearrangement in a Spanish population and to test the specificity of immunohistochemical ERG evaluation for prostate carcinomas. Three prostate tissue microarrays were constructed using radical prostatectomy specimens and related to grade, local invasion, and regional invasion. In addition to samples from malignant cases (160), specimens of prostatic hyperplasia (26) and high-grade prostatic intraepithelial neoplasia (10) were included. Tissue microarrays of 270 samples from most common malignant tumors (breast, colon, lung, and bladder) were also tested. All were analyzed by immunohistochemistry. Seventy-five out of 154 evaluable cases (49 %) of prostate carcinoma showed ERG expression; 52/75 showed strong staining. No ERG expression was observed in any of the high-grade prostatic intraepithelial neoplasia. ERG expression was independent of Gleason score (p = 0.160), extent of invasion (p = 0.517), and regional lymph node involvement (p = 0.816). No ERG expression was found in any other type of tumor, with the exception of one bladder cancer sample that showed focal and weak expression. The frequency of ERG detected in our study correlated with the results published for other Caucasian populations. Strong ERG protein expression was exclusively detected in prostate carcinomas, corroborating the specificity of ERG rearrangements for these tumors. Thus, detecting ERG using immunohistochemistry may be useful in routine practice in pathology departments.

Clinicopathological and molecular characterization of colorectal micropapillary carcinoma.

Invasive micropapillary carcinoma is associated with frequent lymph node metastasis and adverse clinical outcome. Initially described as a variant of breast and ovarian carcinoma, it has subsequently been found in other organs, most recently the colon. Reports of colorectal micropapillary carcinoma to date are limited in number, and their molecular profile has not been established. The aims of the present study were to analyze their clinicopathological features and molecular profile, and compare them with those of conventional adenocarcinoma. Clinicopathological features of a cohort of 379 patients with primary colorectal cancer were retrospectively reviewed for the presence of the pattern characteristic of micropapillary carcinoma. We also assessed the expression of KRT7, KRT20, CEACAM5, MUC1 (EMA, clone E29), MUC1 (clone MA695), MLH1, MSH2, MSH6 and TP53 by immunohistochemistry. Genetic assessments of microsatellite instability, chromosomes 17p and 18q, and mutations in TP53, BRAF and KRAS were performed using DNA extracted from formalin-fixed, paraffin-embedded sections. In all, 60 of the reviewed cases (16%) had a micropapillary component that ranged from 5 to 95% of the tumor, characterized by a higher frequency of an infiltrative pattern, lymphovascular and perineural invasion, a higher depth of invasion and more positive lymph nodes than conventional adenocarcinoma. Immunohistochemistry for MUC1 (clone MA695) and MUC1 (EMA, clone E29) enhanced the characteristic inside-out staining pattern of the micropapillary carcinoma component, whereas the rest of the tumor showed luminal staining patterns. KRT7 expression was slightly increased in micropapillary carcinoma, but did not reach significance (17-3%, P=0.1967). The molecular parameters showed a higher frequency of TP53 alterations and a low incidence of microsatellite instability and RER phenotype (loss of mismatch repair protein) in micropapillary carcinoma. With regard to the histological parameters, micropapillary carcinoma appears to be more aggressive than conventional colorectal adenocarcinoma. The molecular profile supports the hypothesis that micropapillary carcinoma carcinogenesis develops through the classical chromosomal instability pathway.

Microsatellite instability of the colorectal carcinoma can be predicted in the conventional pathologic examination. A prospective multicentric study and the statistical analysis of 615 cases consolidate our previously proposed logistic regression model.

High microsatellite instability (MSI-H) allows the identification of a subset of colorectal carcinomas associated with good prognosis and a higher incidence of Lynch syndrome. The aim of this work was to assess the interobserver variability and optimize our MSI-H prediction model previously published based on phenotypic features.The validation series collected from five different hospitals included 265 primary colorectal carcinomas from the same number of patients. The eight clinicopathological parameters that integrate our original model were evaluated in the corresponding centers. Homogeneity assessment revealed significant differences between hospitals in the estimation of the growth pattern, presence of Crohn-like reaction, percentage of cribriform structures, and Ki-67 positivity. Despite this observation, our model was globally able to predict MSI-H with a negative predictive value of 97.0%. The optimization studies were carried out with 615 cases and resulted in a new prediction model RERtest8, which includes the presence of tumor infiltrating lymphocytes at the expense of the percentage of cribriform structures. This refined model achieves a negative predictive value of 97.9% that is maintained even when the immunohistochemical parameters are left out, RERtest6. The high negative predictive value achieved by our models allows the reduction of the cases to be tested for MSI to less than 10%. Furthermore, the easy evaluation of the parameters included in the model renders it a useful tool for the routine practice and can reinforce other published models and the current clinical protocols to detect the subset of colorectal cancer patients bearing hereditary nonpolyposis colorectal cancers risk and/or MSI-H phenotype.

Androgen receptor CAG and GGC polymorphisms in Mediterraneans: repeat dynamics and population relationships.

Microsatellite variation (CAG and GGC repeats) of the androgen receptor (AR) gene shows remarkable differences among African and non-African populations. In vitro studies have demonstrated an inverse relationship between the length of both microsatellites and AR activity. This fact may explain the observed association of the AR gene with prostate cancer and the strong ethnic differences in the incidence of this cancer. CAG and GGC genetic variation has been tested in a large set of populations from the Ivory Coast as well as 12 Mediterranean samples whose variation is described for the first time. The pattern of frequencies observed in the Ivory Coast agrees with data previously reported for other Sub-Saharan populations. Concerning the Mediterranean variation, Sardinian samples are characterised by low genetic diversities, and Egyptian Siwa Berbers by a particular pattern of GGC frequencies. High and Middle Atlas Moroccan Berbers are the most closely related to the Sub-Saharan variation. For both the CAG and GGC repeats, the Ivory Coast and some Moroccan samples exhibit high frequencies of low size alleles (CAG under 18 repeats, and GGC under 15 repeats) that have been associated with prostate cancer.

A new case of acute nonlymphocytic leukemia (French-American-British subtype M1) with double minutes and c-MYC amplification.

Herein, we present a new case of acute nonlymphocytic leukemia (ANLL) French-American-British M1 subtype with presence of multiple double minutes (dmin) derived from the amplification of the c-MYC oncogene. A review of dmins in ANLL is presented.